RS Aggarwal Solutions for Class 8 Maths Chapter 7 Exercise 7.1: The solutions for RS Aggarwal Class 8 Maths Chapter 7 Exercise 7.1 on factorization have been prepared by the experts of Physics Wallah. These solutions are designed to provide a clear and thorough understanding of factorization concepts.
The experts have broken down each problem step-by-step, ensuring that students can follow along and grasp the underlying principles of factorization with ease. This approach not only helps in solving the exercise problems efficiently but also enhances the student's overall comprehension of the topic.RS Aggarwal Solutions for Class 8 Maths Chapter 7 Exercise 7.1 PDF
Factorise:
(Question 1) (i) 12x + 15
= [(3×4) x] + (3 × 5) = 3(4x + 5)(ii) 14m – 21
= 7 (2m – 3)(iii) 9n – 12n 2
= 3n (3 – 4n)(Question 2) (i) 16a 2 – 24ab
= 8a (2a – 3b)(ii) 15ab 2 – 20a 2 b
= 5ab (3b – 4a)(iii) 12x 2 y 3 – 21x 3 y 2
= 3x 2 y 2 (4y – 7x)(Question 3) (i) 24x 3 – 36x 2 y
= 12x 2 (2x – 3y)(ii) 10x 3 – 15x 2
= 5x 2 (2x – 3)(iii) 36x 3 y – 60x 2 y 3 z
= 12x 2 y (3x – 5y 2 z)(Question 4) (i) 9x 3 – 6x 2 + 12x
= 3x (3x 2 – 2x + 4)(ii) 8x 2 – 72xy + 12x
= 4x (2x – 18y + 3)(iii) 18a 3 b 3 – 27a 2 b 3 + 36a 3 b 2
= 9a 2 b 2 (2ab – 3b + 4a)(Question 5) (i) 14x 3 + 21x 4 y – 28x 2 y 2
= 7x 2 (2x + 3x 2 y – 4y 2 )(ii) – 5 – 10t + 20t 2
= – 5 (1 + 2y – 4t 2 )(Question 6) (i) x(x + 3) + 5(x + 3)
= (x + 3) (x + 5)(ii) 5x(x – 4) – 7(x – 4)
= (x – 4) (5x – 7)(iii) 2m(1 – n) + 3(1 – n)
= (1 – n) (2m + 3)(Question 7) 6a(a – 2b) + 5b(a – 2b)
= (a – 2b) (6a + 5b)(Question 8) x 3 (2a – b) + x 2 (2a – b)
= (2a – b) (x 3 + x 2 ) = x 2 (2a – b) (x + 1)(Question 9) 9a(3a – 5b) – 12a 2 (3a – 5b)
= (3a – 5b) [3a(3 – 4a)] = 3a (3a – 5b) (3 – 4a)(Question 10) (x + 5) 2 – 4(x + 5)
= (x + 5) [(x + 5) – 4] = (x + 5) (x + 1)(Question 11) 3(a – 2b) 2 – 5(a – 2b)
= (a – 2b) (3a – 6b – 5)(Question 12) 2a + 6b – 3(a + 3b) 2
= 2(a + 3b) – 3(a + 3b) 2 = (a + 3b) (2 – 3a – 9b)(Question 13) 16(2p – 3q) 2 – 4(2p – 3q)
= (2p – 3q) (32p – 48q – 4) = 4 (2p – 3q) (8p – 12q – 1)(Question 14) x(a – 3) + y(3 – a)
= x(a – 3) – y(a – 3) = (a – 3) (x – y)(Question 15) 12(2x – 3y) 2 – 16(3y – 2x)
= 12(2x – 3y) 2 + 16(2x – 3y) = (2x – 3y) (24x – 36y + 16) = 4 (2x – 3y) (6x – 9y + 4)(Question 16) (x + y) (2x + 5) – (x + y) (x + 3)
= (x + y) [(2x + 5) – (x + 3)] = (x + y) (2x + 5 – x – 3) = (x + y) (x + 2)(Question 17) ar + br + at + bt
= r (a + b) + t (a + b) = (a + b) (r + t)(Question 18) x 2 – ax – bx + ab
= x (x – a) – b (x – a) = (x – a) (x – b)(Question 19) ab 2 – bc 2 – ab + c 2
= b (ab – c 2 ) – 1(ab – c 2 ) = (ab – c 2 ) (b – 1)(Question 20) x 2 – xz + xy – yz
= x (x – z) + y (x – z) = (x – z) (x + y)(Question 21) 6ab – b 2 + 12ac – 2bc
= b(6a – b) + 2c (6a – b) = (6a – b) (b + 2c)(Question 22) (x – 2y) 2 + 4x – 8y
= (x – 2y) (x – 2y) + 4(x – 2y) = (x – 2y) (x – 2y + 4)(Question 23) y 2 – xy(1 – x) – x 3
= y 2 – xy + x 2 y – x 3 = y(y – x) + x 2 (y – x) = (y – x) (y + x 2 )(Question 24) (ax + by) 2 + (bx – ay) 2
= [(ax) 2 + 2axby + (by) 2 ] + [(bx) 2 – 2bxay + (ay) 2 ] = a 2 x 2 + 2axby + b 2 y 2 + b 2 x 2 – 2axby + a 2 y 2 = a 2 x 2 + b 2 x 2 + a 2 y 2 + b 2 y 2 = x 2 (a 2 + b 2 ) + y 2 (a 2 + b 2 ) = (a 2 + b 2 ) (x 2 + y 2 )(Question 25) ab 2 + (a – 1) b – 1
= ab 2 + ab – b – 1 = ab(b + 1) – 1(b + 1) = (b + 1) (ab – 1)(Question 26) x 3 – 3x 2 + x – 3
= x 2 (x – 3) + 1 (x – 3) = (x – 3) (x 2 + 1)(Question 27) ab(x 2 + y 2 ) – xy(a 2 + b 2 )
= abx 2 + aby 2 – a 2 xy – b 2 xy = abx 2 – a 2 xy – b 2 xy + aby 2 = ax (bx – ay) – by (bx – ay) = (bx – ay) (ax – by)(Question 28) x 2 – x(a + 2b) + 2ab
= x 2 – ax – 2bx + 2ab = x(x – a) – 2b (x – a) = (x – a) (x – 2b)