RS Aggarwal Class 8 Solutions Chapter 7 Factorisation Ex 7E

These Solutions are part of RS Aggarwal Solutions Class 8. Here we have given RS Aggarwal Solutions Class 8 Chapter 7 Factorisation Ex 7E.

Other Exercises

OBJECTIVE QUESTIONS.
Tick the correct answer in each of the following :

Question 1.
Solution:
7a2 – 63b2 = 7 (a2 – 9b2)
= 7 {(a)2 – (3b)2}
= 7 (a – 3b) (a + 36) (d)

Question 2.
Solution:
2x – 32x3 = 2x (1 – 16x2)
= 2x {(1)2 – (4x)2}
= 2x (1 – 4x) (1 + 4x) (d)

Question 3.
Solution:
x3 – 144x
= x (x2 – 144)
= x {(x)2 – (12)2}
= x (x – 12) (x + 12) (c)

Question 4.
Solution:
2 – 50x2 = 2 (1 – 25x2)
= 2 {(1)2 – (5x)2}
= 2 (1 – 5x) (1 + 5x) (d)

Question 5.
Solution:
a2 + bc + ab + ac
= a2 + ab + ac + bc
= a (a + b) + c (a + b)
= (a + b) (a + c)   (a)

Question 6.
Solution:
pq2 + q (p – 1) – 1
= pq2 + pq – q – 1
= pq (q + 1) – 1 (q + 1)
= (q + 1) (pq – 1)
= (pq – 1) (q + 1) (d)

Question 7.
Solution:
ab – mn + an – bm
= ab + an – bm – mn
= a (b + n) – m (b + n)
= (b + n) (a – m) (b)

Question 8.
Solution:
ab – a – b + 1
= a (b – 1) – 1 (b – 1)
= b – 1) (a – 1) (a)

Question 9.
Solution:
x2 – xz + xy – yz
= x (x – z) + y (x – z)
= (x – z) (x + y) (c)

Question 10.
Solution:
12m2 – 21
= 3 (4m2 – 9)
= 3 {(2m)2 – (3)2}
= 3 (2m – 3) (2m + 3) (c)

Question 11.
Solution:
x3 – x
= x (x2 – 1)
= x (x – 1) (x + 1) (d)

Question 12.
Solution:
1 – 2ab – (a2 + b2)
= 1 – 2ab – a2 – b2
= 1 – (a2 + b2 + 2ab)
= 1 – (a + b)2
= (1 + a + b) (1 – a – b) (c)

Question 13.
Solution:
x2 + 6x + 8
= x2 + 4x + 2x + 8
{8 = 4 x 2, 6 = 4 + 2}
= x (x + 4) + 2 (x + 4)
= (x + 4) (x + 2) (c)

Question 14.
Solution:
x2 + 4x – 21
= x2 + 7x – 3x – 21
{ – 21 = + 7 x ( – 3), 4 = 7 – 3}
= x (x + 7) – 3 (x + 7)
= (x + 7) (x – 3) (b)

Question 15.
Solution:
y2 + 2y – 3
{ – 3 = 3 x ( – 1), 2 = 3 – 1}
= y2 + 3y – y – 3
= y (y + 3) – 1 (y + 3)
= (y + 3) (y – 1) (a)

Question 16.
Solution:
40 + 3x – x2
= 40 + 8x – 5x -x2
{40 = 8 x ( – 5), 3 = 8 – 5}
= 8(5 + x) – x(5 + x)
= (5 + x)(8 – x) (c)

Question 17.
Solution:
2x2 + 5x + 3
= 2x2 + 2x + 3x + 3
{2 x 3 = 6, 6 = 2 x 3, 5 = 2 + 3}
= 2x(x + 1) + 3(x + 1)
= (x + 1)(2x + 3) (b)

Question 18.
Solution:
6a2 – 13a + 6
= 6a2 – 9a – 4a + 6
{6 x 6 = 36, 36 = ( – 9)x( – 4), – 13 = – 9 – 4}
= 3a (2a – 3) – 2 (2a – 3)
= (2a – 3) (3a – 2) (c)

Question 19.
Solution:
4z2 – 8z + 3
= 4z2 – 6z – 2z + 3
{4 x 3 = 12,12 = ( – 6)x( – 2), – 8 = – 6 – 2}
= 2z (2z – 3) – 1 (2z – 3)
= (2z – 3) (2z – 1) (a)

Question 20.
Solution:
3 + 23y – 8y2
= 3 + 24y – y – 8y2
{3 x ( – 8) = – 24, – 24 = 24 x ( – 1), 23 = 24 – 1}
= 3(1 + 8y) – y(1 + 8y)
= (1 + 8y) (3 – y) (b)

Hope given RS Aggarwal Solutions Class 8 Chapter 7 Factorisation Ex 7E are helpful to complete your math homework.

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