NCERT Solutions have been carefully compiled and developed considering the latest syllabus. CBSE Class 8 Maths, Chapter 9 Exercise 9.3, exercise questions and answers help students to understand the multiplication of the two polynomials as well as the simplification of an expression at particular values. NCERT Solutions for Class 8 Maths Chapter 9 Algebraic Expressions and Identities Exercise 9.3 are prepared using a step-by-step approach and aim to improve problem-solving skills. Download free NCERT Solutions for Maths Chapter 9 prepared by BYJU’S subject experts and practise offline.
NCERT Solutions for Class 8 Maths Chapter 9 Algebraic Expressions and Identities Exercise 9.3
Access Answers to NCERT Class 8 Maths Chapter 9 Algebraic Expressions and Identities
Exercise 9.3 Page No: 146
1. Carry out the multiplication of the expressions in each of the following pairs.
(i) 4p, q + r
(ii) ab, a – b
(iii) a + b, 7a²b²
(iv) a2 – 9, 4a
(v) pq + qr + rp, 0
Solution:
(i)4p(q + r) = 4pq + 4pr
(ii)ab(a – b) = a2 b – a b2
(iii)(a + b) (7a2b2) = 7a3b2Â + 7a2b3
(iv) (a2 – 9)(4a) = 4a3 – 36a
(v) (pq + qr + rp) × 0 = 0 ( Anything multiplied by zero is zero )
2. Complete the table.
Solution:
| First expression | Second expression | Product | |
| (i) | a | b + c + d | a(b+c+d)
= a×b + a×c + a×d = ab + ac + ad |
| (ii) | x + y – 5 | 5xy | 5 xy (x + y – 5)
= 5 xy x x + 5 xy x y – 5 xy x 5 = 5 x2y + 5 xy2 – 25xy |
| (iii) | p | 6p2 – 7p + 5 | p (6 p 2-7 p +5)
= p× 6 p2 – p× 7 p + p×5 = 6 p3 – 7 p2 + 5 p |
| (iv) | 4 p2 q2 | p2 – q2 | 4p2 q2 x (p2 – q2 )
=4 p4 q2 – 4p2 q4 |
| (v) | a + b + c | abc | abc(a + b + c)
= abc × a + abc × b + abc × c = a2bc + ab2c + abc2 |
3. Find the product.
i) a2Â x (2a22) x (4a26)
ii) (2/3 xy) ×(-9/10 x2y2)
(iii) (-10/3 pq3/) × (6/5 p3q)
(iv) ( x) × (x2) × (x3) × (x4)
Solution:
i) a2 x (2a22) x (4a26) = (2 × 4) ( a2 × a22 × a26 ) = 8 × a2 + 22 + 26 = 8a50
ii) (2xy/3) ×(-9x2y2/10)
=(2/3 × -9/10 ) ( x × x2 × y × y2 )
= (-3/5 x3y3)
iii) (-10pq3/3) ×(6p3q/5)
= ( -10/3 × 6/5 ) (p × p3 × q3 × q)
= (-4p4q4)
iv)  ( x) x (x2) x (x3) x (x4)
= x1 + 2 + 3 + 4Â
=Â x10
4. (a) Simplify 3x (4x – 5) + 3 and find its values for (i) x = 3 (ii) x =1/2
(b) Simplify a (a2+ a + 1) + 5 and find its value for (i) a = 0, (ii) a = 1 (iii) a = – 1.
Solution:
(a) 3x (4x – 5) + 3
=3x ( 4x) – 3x( 5) +3
=12x2Â – 15x + 3
(i) Putting x=3 in the equation we gets
12x2 – 15x + 3 =12(32) – 15 (3) +3
= 108 – 45 + 3 = 66
(ii) Putting x=1/2 in the equation we get
12x2 – 15x + 3 = 12 (1/2)2 – 15 (1/2) + 3
=12 (1/4) – 15/2 +3
= 3 – 15/2 + 3
= 6- 15/2
= (12- 15 ) /2
= -3/2
(b) a(a2 +a +1)+5
=a x a2 + a x a + a x 1 + 5
=a3+a2+a+ 5
(i) putting a= 0 in the equation we get
03+02+0+5=5
(ii) putting a=1 in the equation we get
13Â + 12Â + 1+5 = 1 + 1 + 1+5 = 8
(iii) Putting a = -1 in the equation we get
(-1)3+(-1)2 + (-1)+5 = -1 + 1 – 1+5 = 4
5. (a) Add: p ( p – q), q ( q – r) and r ( r – p)
(b) Add: 2x (z – x – y) and 2y (z – y – x)
(c) Subtract: 3l (l – 4 m + 5 n) from 4l ( 10 n – 3 m + 2 l )
(d) Subtract: 3a (a + b + c ) – 2 b (a – b + c)  from 4c ( – a + b + c )
Solution:
a) p ( p – q) + q ( q – r) + r ( r – p)
= (p2Â – pq) + (q2Â – qr) + (r2Â – pr)
= p2Â + q2Â + r2Â – pq – qr – pr
b) 2x (z – x – y) + 2y (z – y – x)
= (2xz – 2x2Â – 2xy) + (2yz – 2y2Â – 2xy)
= 2xz – 4xy + 2yz – 2x2Â – 2y2
c) 4l ( 10 n – 3 m + 2 l ) – 3l (l – 4 m + 5 n)
=(40ln – 12lm + 8l2) – (3l2Â – 12lm + 15ln)
= 40ln – 12lm + 8l2Â – 3l2Â +12lm -15 ln
= 25 ln + 5l2
d) 4c ( – a + b + c ) – (3a (a + b + c ) – 2 b (a – b + c))
= (-4ac + 4bc + 4c2) – (3a2 + 3ab + 3ac – ( 2ab – 2b2 + 2bc ))
=-4ac + 4bc + 4c2 – (3a2Â + 3ab + 3ac – 2ab + 2b2 – 2bc)
= -4ac + 4bc + 4c2 – 3a2 – 3ab – 3ac +2ab – 2b2 + 2bc
= -7ac + 6bc + 4c2 – 3a2 – ab – 2b2
Access Other Exercise Solutions of Class 8 Maths Chapter 9 Algebraic Expressions and Identities
Exercise 9.1 Solutions: 4 Questions (Short answers)
Exercise 9.2 Solutions: 5 Questions (Short answers)
Exercise 9.4 Solutions: 3 Questions (Short answers)
Exercise 9.5 Solutions: 8 Questions (Short answers)
NCERT Solutions for Class 8 Maths Chapter 9 Algebraic Expressions and Identities Exercise 9.3
NCERT Solutions for Class 8 Maths Chapter 9 Algebraic Expressions and Identities Exercise 9.3 is about the multiplication of a monomial by a binomial, multiplying a monomial by a trinomial and simplification of the expressions and their values for given points. Practise exercise problems and complete your homework on time.
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