NCERT Solutions for Class 8 Maths Chapter 9 Algebraic Expressions and Identities
NCERT solutions for class 8 maths chapter 9 algebraic expressions and identities topic 9.1 what are expressions?
Question: 1 Give five examples of expressions containing one variable and five examples of expressions containing two variables.
Answer:
Five examples of expressions containing one variable are:
Five examples of expressions containing two variables are:
Question: 2(i) Show on the number line :
Answer:
x on the number line:
Question: 2(ii) Show on the number line :
Answer:
x-4 on the number line:
Question: 2(iii) Show on the number line :
2x+1
Answer:
2x+1 on the number line:
Question: 2(iv) Show on the number line:
Answer:
3x - 2 on the number line
NCERT solutions for class 8 maths chapter 9 algebraic expressions and identities topic 9.2 terms, factors and coefficients
Question:1 Identify the coefficient of each term in the expression.
Answer:
coefficient of each term are given below
NCERT solutions for class 8 maths chapter 9 algebraic expressions and identities topic 9.3 monomials, binomials and polynomials
Question: 1(i) Classify the following polynomials as monomials, binomials, trinomials.
Answer:
Binomial since there are two terms with non zero coefficients.
Question: 1(ii) Classify the following polynomials as monomials, binomials, trinomials.
Answer:
Trinomial since there are three terms with non zero coefficients.
Question:1(iii) Classify the following polynomials as monomials, binomials, trinomials.
Answer:
Trinomial since there are three terms with non zero coefficients.
Question: 1(iv) Classify the following polynomials as monomials, binomials, trinomials.
Answer:
Binomial since there are two terms with non zero coefficients.
Question: 1(v) Classify the following polynomials as monomials, binomials, trinomials.
Answer:
Monomial since there is only one term.
Question: 2(a) Construct 3 binomials with only as a variable;
Answer:
Three binomials with the only x as a variable are:
Question: 2(b) Construct 3 binomials with and as variables;
Answer:
Three binomials with x and y as variables are:
Question: 2(c) Construct 3 monomials with and as variables;
Answer:
Three monomials with x and y as variables are
Question: 2(d) Construct 2 polynomials with 4 or more terms .
Answer:
Two polynomials with 4 or more terms are:
NCERT solutions for class 8 maths chapter 9 algebraic expressions and identities topic 9.4 like and unlike terms
Question:(i) Write two terms which are like
Answer:
Question:(ii) Write two terms which are like
Answer:
we can write more like terms
Question:(iii) Write two terms which are like
Answer:
NCERT solutions for class 8 maths chapter 9 algebraic expressions and identities-Exercise: 9.1
Question:1(i) Identify the terms, their coefficients for each of the following expressions.
Answer
following are the terms and coefficient
The terms are and the coefficients are 5 and -3.
Question: 1(ii) Identify the terms, their coefficients for each of the following expressions.
Answer:
the following is the solution
Question:1(iii) Identify the terms, their coefficients for each of the following expressions.
Answer:
Question: 1(iv) Identify the terms, their coefficients for each of the following expressions.
Answer:
The terms are 3, -pq, qr,and -rp and the coefficients are 3, -1, 1 and -1 respectively.
Question:1(v) Identify the terms, their coefficients for each of the following expressions.
Answer:
Above are the terms and coefficients
Question: 1(vi) Identify the terms, their coefficients for each of the following expressions.
Answer:
The terms are 0.3a, -0.6ab and 0.5b and the coefficients are 0.3, -0.6 and 0.5.
Question: 2(a) Classify the following polynomials as monomials, binomials, trinomials. Which polynomials do not fit in any of these three categories?
Answer:
Binomial.
Question: 2(b) Classify the following polynomials as monomials, binomials, trinomials. Which polynomials do not fit in any of these three categories?
Answer:
Monomial.
Question: 2(c) Classify the following polynomials as monomials, binomials, trinomials. Which polynomials do not fit in any of these three categories?
Answer:
This polynomial does not fit in any of these three categories.
Question: 2(d) Classify the following polynomials as monomials, binomials, trinomials. Which polynomials do not fit in any of these three categories?
Answer:
Trinomial.
Question: 2(e) Classify the following polynomials as monomials, binomials, trinomials. Which polynomials do not fit in any of these three categories?
Answer:
Binomial.
Question: 2(f) Classify the following polynomials as monomials, binomials, trinomials. Which polynomials do not fit in any of these three categories?
Answer:
Trinomial.
Question: 2(g) Classify the following polynomials as monomials, binomials, trinomials. Which polynomials do not fit in any of these three categories?
Answer:
Trinomial.
Question: 2(h) Classify the following polynomials as monomials, binomials, trinomials. Which polynomials do not fit in any of these three categories?
Answer:
Binomial.
Question: 2(i) Classify the following polynomials as monomials, binomials, trinomials. Which polynomials do not fit in any of these three categories?
Answer:
This polynomial does not fit in any of these three categories.
Question:2(j) Classify the following polynomials as monomials, binomials, trinomials. Which polynomials do not fit in any of these three categories?
Answer:
Monomial.
Question: 2(k) Classify the following polynomials as monomials, binomials, trinomials. Which polynomials do not fit in any of these three categories?
Answer:
Binomial.
Question: 2(i) Classify the following polynomials as monomials, binomials, trinomials. Which polynomials do not fit in any of these three categories?
Answer:
Binomial.
Question: 3(i) Add the following.
Answer:
ab-bc+bc-ca+ca-ab=0.
Question:3 (ii) Add the following.
Answer:
Question:3 (iii) Add the following
Answer:
Question: 3(iv) Add the following.
Answer:
Question: 4(a) Subtract from
Answer:
12a-9ab+5b-3-(4a-7ab+3b+12)
=(12-4)a +(-9+7)ab+(5-3)b +(-3-12)
=8a-2ab+2b-15
Question: 4(b) Subtract from
Answer:
Question: 4(c) Subtract from
Answer:
NCERT solutions for class 8 maths chapter 9 algebraic expressions and identities topic 9.7.2 multiplying three or more monomials
Question:1 Find . First find and multiply it by ; or first find and multiply it by .
Answer:
We observe that the result is same in both cases and the result does not depend on the order in which multiplication has been carried out.
NCERT solutions for class 8 maths chapter 9 algebraic expressions and identities-Exercise: 9.2
Question: 1(i) Find the product of the following pairs of monomials.
Answer:
Question: 1(ii) Find the product of the following pairs of monomials.
Answer:
<img alt="\\-4p\times 7p\\=(-4\times 7)p\times p\\=-28p^{2}" height="61"
src="https://lh3.googleusercontent.com/ZQLwJFEoi48QnxUuK79XbVO1Ug-ZvBoOflH3wFRfnzdHsH_uWOVnOwg4kaF8g0o8RSXTEfDcwrA7mDeS0UuxfpygL0vqvj2Ip_Ntb3J0UEOs2WBYddLAm3Ff_WG8HAzyPrqB_V0" style="margin-left: 0px; margin-top: 0px;" width="128" />
Question: 1(iii) Find the product of the following pairs of monomials
Answer:
Question: 1(iv) Find the product of the following pairs of monomials.
Answer:
Question:1(v) Find the product of the following pairs of monomials.
Answer:
Question:2(A) Find the areas of rectangles with the following pairs of monomials as their lengths and breadths respectively.
Answer:
The question can be solved as follows
Question:2(B) Find the areas of rectangles with the following pairs of monomials as their lengths and breadth respectively.
Answer:
the area is calculated as follows
Question:2(C) Find the areas of rectangles with the following pairs of monomials as their lengths and breadths respectively.
Answer:
the following is the solution
Question:2(D) Find the areas of rectangles with the following pairs of monomials as their lengths and breadths respectively.
Answer:
area of rectangles is
Question:2(E) Find the areas of rectangles with the following pairs of monomials as their lengths and breadths respectively.
Answer:
The area is calculated as follows
Question:3 Complete the table of products.
First monomial Second monomial |
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Answer:
First monomial Second monomial |
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Question:4(i) Obtain the volume of rectangular boxes with the following length, breadth and height respectively.
Answer:
Question:4(ii) Obtain the volume of rectangular boxes with the following length, breadth and height respectively.
Answer:
the volume of rectangular boxes with the following length, breadth and height is
Question:4(iii) Obtain the volume of rectangular boxes with the following length, breadth and height respectively.
Answer:
the volume of rectangular boxes with the following length, breadth and height is
Question:4(iv) Obtain the volume of rectangular boxes with the following length, breadth and height respectively.
Answer:
the volume of rectangular boxes with the following length, breadth and height is
Question:5(i) Obtain the product of
Answer:
the product
Question:5(ii) Obtain the product of
Answer:
the product
Question:5(iii) Obtain the product of
Answer:
the product
Question:5(iv) Obtain the product of
Answer:
the product
Question:5(v) Obtain the product of
Answer:
the product
NCERT solutions for class 8 maths chapter 9 algebraic expressions and identities topic 9.8.1 multiplying a monomial by a binomial
Question:(i) Find the product
Answer:
Using distributive law,
Question:(ii) Find the product
Answer:
Using distributive law,
We have :
NCERT solutions for class 8 maths chapter 9 algebraic expressions and identities topic 9.8.2 multiplying a monomial by a trinomial
Question:1 Find the product:
Answer:
By using distributive law,
NCERT solutions for class 8 maths chapter 9 algebraic expressions and identities-Exercise: 9.3
Question:1(i) Carry out the multiplication of the expressions in each of the following pairs.
Answer:
Multiplication of the given expression gives :
By distributive law,
Question:1(ii) Carry out the multiplication of the expressions in each of the following pairs.
Answer:
We have ab, (a-b).
Using distributive law we get,
Question:1(iii) Carry out the multiplication of the expressions in each of the following pairs.
Answer:
Using distributive law we can obtain multiplication of given expression:
<img alt="(a + b)(7a^2b^2) = 7a^3b^2 + 7a^2b^3" height="20"
src="https://lh6.googleusercontent.com/zym-v6hoY_4dPgfdHnN35kmtdqAvE_B4CvAHBzx42tg4OdnWGpufkQNURYQP8yq9xk7qpbbNA_sAzgb0gc0AnG0Vxa5aU4snOBR80IU5GQ_6VDoRBqkDdZGjqZfE11JML0vyGTI" style="margin-left: 0px; margin-top: 0px;" width="232" />
Question:1(iv) Carry out the multiplication of the expressions in each of the following pairs.
Answer:
We will obtain multiplication of given expression by using distributive law :
Question:1(v) Carry out the multiplication of the expressions in each of the following pairs.
Answer:
Using distributive law :
Question:2 Complete the table
First expression |
Second expression |
Product |
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(i) |
... |
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(ii) |
... |
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(iii) |
... |
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(iv) |
... |
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(v) |
... |
Answer:
We will use distributive law to find product in each case.
First expression |
Second expression |
Product |
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(i) |
|||
(ii) |
|||
(iii) |
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(iv) |
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(v) |
Question:3(i) Find the product.
Answer:
Opening brackets :
or
Question:3(ii) Find the product.
Answer:
We have,
Question:3(iii) Find the product.
Answer:
We have
Question:3(iv) Find the product.
Answer:
We have
or
Question:4(a) Simplify and find its values for
(i)
Answer:
(a) We have
Put x = 3,
We get :
Question:4(a) Simplify and find its values for
(ii)
Answer:
We have
Put
. So We get,
Question:4(b) Simplify and find its value for
(i)
Answer:
We have :
Put a = 0 :
Question:4(b) Simplify and find its value for
(ii)
Answer:
We have
Put a = 1 ,
we get :
Question:4(b) Simplify and find its value for
(iii)
Answer:
We have .
or
Put a = (-1)
Question:5(a) Add: and
Answer:
(a)First we will solve each brackets individually.
; ;
Addind all we get :
Question:5(b) Add: and
Answer:
Firstly, open the brackets:
and
Adding both, we get :
or
Question:5(c) Subtract: from
Answer:
At first we will solve each bracket individually,
and
Subtracting:
or
or
Question:5(d) Subtract: from
Answer:
Solving brackets :
and
Subtracting :
NCERT solutions for class 8 maths chapter 9 algebraic expressions and identities-Exercise: 9.4
Question:1(i) Multiply the binomials.
and
Answer:
We have (2x + 5) and (4x - 3)
(2x + 5) X (4x - 3) = (2x)(4x) + (2x)(-3) + (5)(4x) + (5)(-3)
= 8 - 6x + 20x - 15
= 8 + 14x -15
Question:1(ii) Multiply the binomials.
and
Answer:
We need to multiply (y - 8) and (3y - 4)
(y - 8) X (3y - 4) = (y)(3y) + (y)(-4) + (-8)(3y) + (-8)(-4)
= 3 - 4y - 24y + 32
= 3 - 28y + 32
Question:1(iii) Multiply the binomials
and
Answer:
We need to multiply (2.5l - 0.5m) and (2.5l + 0..5m)
(2.5l - 0.5m) X (2.5l + 0..5m) = using
= 6.25 - 0.25
Question:1(iv) Multiply the binomials.
and
Answer:
(a + 3b) X (x + 5) = (a)(x) + (a)(5) + (3b)(x) + (3b)(5)
= ax + 5a + 3bx + 15b
Question:1(v) Multiply the binomials.
<img alt="\small (2pq+3q^2)" height="19"
src="https://lh4.googleusercontent.com/faqbYXt8AEy2TVr4J1p5vfUz45qyR0d4muq8Xtx5GLLq1Q_3ixfJjPaV3qC_ucxFJnviMKxD4XzZothad36SoNOFM4fgPw4kUMXa3b14Bf5s7YQDTAuZkKh5Nzh92lnwz2Fa810" style="margin-left: 0px; margin-top: 0px;" width="79" /> and
Answer:
(2pq + 3q 2 ) X (3pq - 2q 2 ) = (2pq)(3pq) + (2pq)(-2q 2 ) + ( 3q 2 )(3pq) + (3q 2 )(-2q 2 )
= 6p 2 q 2 - 4pq 3 + 9pq 3 - 6q 4
= 6p 2 q 2 +5pq 3 - 6q 4
Question:1(vi) Multiply the binomials.
and
Answer:
Multiplication can be done as follows
X =
=
=
Question:2(i) Find the product.
Answer:
(5 - 2x) X (3 + x) = (5)(3) + (5)(x) +(-2x)(3) + (-2x)(x)
= 15 + 5x - 6x - 2
= 15 - x - 2
Question:2(ii) Find the product.
Answer:
(x + 7y) X (7x - y) = (x)(7x) + (x)(-y) + (7y)(7x) + (7y)(-y)
= 7 - xy + 49xy - 7
= 7 + 48xy - 7
Question:2(iii) Find the product.
Answer:
( + b) X (a + ) = ( )(a) + ( )( ) + (b)(a) + (b)( )
=
Question:2(iv) Find the product.
Answer:
following is the solution
( ) X (2p + q) =
Question:3(i) Simplify.
Answer:
this can be simplified as follows
( -5) X (x + 5) + 25 = ( )(x) + ( )(5) + (-5)(x) + (-5)(5) + 25
=
=
Question:3(ii) Simplify .
Answer:
This can be simplified as
( + 5) X ( + 3) + 5 = ( )( ) + ( )(3) + (5)( ) + (5)(3) + 5
=
=
Question:3(iii) Simplify.
Answer:
simplifications can be
(t + )( - s) = (t)( ) + (t)(-s) + ( )( ) + ( )(-s)
=
Question:3(iv) Simplify.
Answer:
(a + b) X ( c -d) + (a - b) X (c + d) + 2(ac + bd )
= (a)(c) + (a)(-d) + (b)(c) + (b)(-d) + (a)(c) + (a)(d) + (-b)(c) + (-b)(d) + 2(ac + bd )
= ac - ad + bc - bd + ac +ad -bc - bd + 2(ac + bd )
= 2(ac - bd ) + 2(ac +bd )
= 2ac - 2bd + 2ac + 2bd
= 4ac
Question:3(v) Simplify.
Answer:
(x + y) X ( 2x + y) + (x + 2y) X (x - y)
=(x)(2x) + (x)(y) + (y)(2x) + (y)(y) + (x)(x) + (x)(-y) + (2y)(x) + (2y)(-y)
= 2 + xy + 2xy + + - xy + 2xy - 2
=3 + 4xy -
Question:3(vi) Simplify.
Answer:
simplification is done as follows
(x + y) X ( ) = x X ( ) + y ( )
=
=
Question:3(vii) Simplify.
Answer:
(1.5x - 4y) X (1.5x + 4y + 3) - 4.5x + 12y = (1.5x) X (1.5x + 4y + 3) -4y X (1.5x + 4y + 3) - 4.5x + 12y
= 2.25 + 6xy + 4.5x - 6xy - 16 - 12y -4.5x + 12 y
= 2.25 - 16
Question:3(viii) Simplify.
Answer:
(a + b + c) X (a + b - c) = a X (a + b - c) + b X (a + b - c) + c X (a + b - c)
= + ab - ac + ab + -bc + ac + bc -
= + - + 2ab
NCERT solutions for class 8 maths chapter 9 algebraic expressions and identities topic 9.11 standerd identities
Question:1(i) Put -b in place of b in identity 1. Do you get identity 2?
Answer:
Identity 1
If we replace b with -b in identity 1
We get,
which is equal to
which is identity 2
So, we get identity 2 by replacing b with -b in identity 1
NCERT free solutions for class 8 maths chapter 9 algebraic expressions and identities topic 9.11 standard identities
Question:1 Verify Identity (IV), for .
Answer:
Identity IV
(a + x)(b + x) =
So, it is given that a = 2, b = 3 and x = 5
Lets put these value in identity IV
(2 + 5)(3 + 5) = + (2 + 3)5 +2 X 3
7 X 8 = 25 + 5 X 5 + 6
56 = 25 + 25 + 6
= 56
L.H.S. = R.H.S.
So, by this we can say that identity IV satisfy with given value of a,b and x
Question:2 Consider, the special case of Identity (IV) with a = b, what do you get? Is it related to Identity
Answer:
Identity IV is
If a =b than
(a + x)(a + x) =
Which is identity I
Question:3 Consider, the special case of Identity (IV) with and What do you get? Is it related to Identity ?
Answer:
Identity IV is
If a = b = -c than,
(x - c)(x - c) =
Which is identity II
Question:4 Consider the special case of Identity (IV) with . What do you get? Is it related to Identity?
Answer:
Identity IV is
If b = -a than,
(x + a)(x - a) =
=
Which is identity III
NCERT solutions for class 8 maths chapter 9 algebraic expressions and identities-Exercise: 9.5
Question:1(i) Use a suitable identity to get each of the following products.
Answer:
(x + 3) X (x +3) =
So, we use identity I for this which is
In this a=x and b = x
=
Question:1(ii) Use a suitable identity to get each of the following products in bracket.
Answer:
(2y + 5) X ( 2y + 5) =
We use identity I for this which is
IN this a = 2y and b = 5
=
Question:1(iii) Use a suitable identity to get each of the following products in bracket.
Answer:
(2a -7) X (2a - 7) =
We use identity II for this which is
in this a = 2a and b = 7
=
Question:1(iv) Use a suitable identity to get each of the following products in bracket.
Answer:
We use identity II for this which is
in this a = 3a and b = -1/2
=
Question:1(v) Use a suitable identity to get each of the following products in bracket.
Answer:
We use identity III for this which is
(a - b)(a + b) =
In this a = 1.1m and b = 4
=
= 1.21 - 16
Question:1(vi) Use a suitable identity to get each of the following products in bracket.
Answer:
take the (-)ve sign common so our question becomes
-
We use identity III for this which is
(a - b)(a + b) =
In this a = and b =
=
Question:1(vii) Use a suitable identity to get each of the following.
Answer:
(6x -7) X (6x - 7) =
We use identity III for this which is
(a - b)(a + b) =
In this a = 6x and b = 7
(6x -7) X (6x - 7) =
Question:1(viii) Use a suitable identity to get each of the following product.
Answer:
take (-)ve sign common from both the brackets So, our question become
(a -c) X (a -c) =
We use identity II for this which is
In this a = a and b = c
Question:1(ix) Use a suitable identity to get each of the following product.
Answer:
We use identity I for this which is
In this a = and b =
=
Question:1(x) Use a suitable identity to get each of the following products.
Answer:
We use identity II for this which is
In this a = 7a and b = 9b
=
Question:2(i) Use the identity to find the following products.
Answer:
We use identity
in this a = 3 and b = 7
=
=
Question:2(ii) Use the identity to find the following products.
Answer:
We use identity
In this a= 5 , b = 1 and x = 4x
=
=
Question:2(iii) Use the identity to find the following products.
Answer:
We use identity
in this x = 4x , a = -5 and b = -1
=
=
Question:1(iv) Use the identity to find the following products.
Answer:
We use identity
In this a = 5 , b = -1 and x = 4x
=
=
Question:2(v) Use the identity to find the following products.
Answer:
We use identity
In this a = 5y , b = 3y and x = 2x
=
=
Question:2(vi) Use the identity to find the following products.
Answer:
We use identity
In this a = 9 , b = 5 and x = <img alt="2a^{2}" height="16"
src="https://lh5.googleusercontent.com/2qHQF6RatvqmP_IzaprdObn1TW7Qc6P5ahuw5OBgw979_B5ENMeSRnBhk9M65bsGhcIIOjA5Z-Tfx4RDq34UjzRxIxPbAH48O8Ack3-cw0InSk7MCot84kU1ew5darMTXngAh6s" style="margin-left: 0px; margin-top: 0px;" width="24" />
=
=
Question:2(vii) Use the identity to find the following products.
Answer:
We use identity
In this a = -4 , b = -2 and x = xyz
=
=
Question:3(i) Find the following squares by using the identities.
Answer:
We use identity
In this a =b and b = 7
=
Question:3(ii) Find the following squares by using the identities.
Answer:
We use
In this a = xy and b = 3z
=
Question:3(iii) Find the following squares by using the identities.
Answer:
We use
In this a = and b =
=
Question:3(iv) Find the following squares by using the identities.
Answer:
we use the identity
In this a = and b =
=
Question:3(v) Find the following squares by using the identities.
Answer:
we use
In this a = 0.4p and b =0.5q
=
Question:3(vi) Find the following squares by using the identities.
Answer:
we use the identity
In this a = 2xy and b =5y
=
Question:4(i) Simplify:
Answer:
we use
In this a = and b =
=
Question:4(ii) Simplify.
Answer:
we use
In this a = (2x + 5) and b = (2x - 5)
=
= (4x)(10)
=40x
or
remember that
here a= 2x, b= 5
Question:4(iii) Simplify.
Answer:
we use
and
In this a = 7m and b = 8n
=
and
=
So, = +
=
or
remember that
Question: 4(iv) Simplify.
Answer:
we use
1 ) In this a = 4m and b = 5n
=
2 ) in this a = 5m and b = 4n
=
So, = +
=
Question: 4(v) Simplify.
Answer:
we use
1 ) In this a = (2.5p- 1.5q) and b = (1.5p - 2.5q)
=
= 4(p + q ) (p - q)
= 4
Question:4(vi) Simplify.
Answer:
We use identity
In this a = ab and b = bc
=
Now, -
=
Question:4(vii) Simplify.
Answer:
We use identity
In this a = and b =
=
Now, +
=
Question:5(i) Show that
Answer:
L.H.S. =
= R.H.S.
Hence it is prooved
Question:5(ii) Show that
Answer:
L.H.S. = (Using )
= R.H.S.
Question:5(iii) Show that.
Answer:
First we will solve the LHS :
or
= RHS
Question:5(iv) Show that.
Answer:
Opening both brackets we get,
= R.H.S.
Question:5(v) Show that
Answer:
Opening all brackets from the LHS, we get :
= RHS
Question:6(i) Using identities, evaluate.
Answer:
We will use the identity:
So,
Question:6(ii) Using identities, evaluate.
Answer:
Here we will use the identity :
So :
or
Question:6(iii) Using identities, evaluate.
Answer:
Here we will use the identity :
So :
or
Question:6(iv) Using identities, evaluate.
Answer:
Here we will the identity :
or
or
Question:6(v) Using identities, evaluate.
Answer:
Here we will use :
Thus
or
Question:6(vi) Using identities, evaluate.
Answer:
This can be written as :
using
or
Question:6(vii) Using identities, evaluate.
Answer:
This can be written in form of :
or
or
Question:6(viii) Using identities, evaluate.
Answer:
Here we will use the identity :
Thus :
or
or
Question:6(ix) Using identities, evaluate.
Answer:
This can be written as :
or
or
or
Question:7(i) Using , find
Answer:
We know,
Using this formula,
= (51 + 49)(51 - 49)
= (100)(2)
= 200
Question:7(ii) Using , find
Answer:
We know,
Using this formula,
= (1.02 + 0.98)(1.02 - 0.98)
= (2.00)(0.04)
= 0.08
Question:7(iii) Using , find.
Answer:
We know,
Using this formula,
= (153 - 147)(153 +147)
=(6) (300)
= 1800
Question:7(iv) Using , find
Answer:
We know,
Using this formula,
= (1.02 + 0.98)(1.02 - 0.98)
= (2.00)(0.04)
= 0.08
Question:8(i) Using
Answer:
We know,
Using this formula,
= (100 + 3)(100 + 4)
Here x =100, a = 3, b = 4
= 11212
Question:8(ii) Using , find
Answer:
We know,
Using this formula,
= (5 + 0.1)(5 + 0.2)
Here x =5, a = 0.1, b = 0.2
= 26.52
Question:8(iii) Using , find
Answer:
We know,
Using this formula,
= (100 + 3)(100 - 2) = (100 + 3){100 + (-2)}
Here x =100, a = 3, b = -2
= 10094
Question: 8(iv) Using , find
Answer:
We know,
Using this formula,
= (10 - 0.3)(10 - 0.2) = {10 + (-0.3)}{10 + (-0.2)}
Here x =10, a = -0.3, b = -0.2
= 95.
NCERT Class 8 Mathematics Solutions
Chapter 02 - Linear Equations in One Variable
Chapter 03 -Understanding Quadrilaterals
Chapter 04 - Practical Geometry
Chapter 06 - Squares and Square Roots
Chapter 07 - Cubes and Cube Roots
Chapter 08 - Comparing Quantities
Chapter 09 - Algebraic Expressions and Identities
Chapter 10 - Visualising Solid Shapes
Chapter 12 - Exponents and Powers
Chapter 13 - Direct and Indirect proportions