## 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**

- RS Aggarwal Solutions Class 8 Chapter 7 Factorisation Ex 7A
- RS Aggarwal Solutions Class 8 Chapter 7 Factorisation Ex 7B
- RS Aggarwal Solutions Class 8 Chapter 7 Factorisation Ex 7C
- RS Aggarwal Solutions Class 8 Chapter 7 Factorisation Ex 7D
- RS Aggarwal Solutions Class 8 Chapter 7 Factorisation Ex 7E

**OBJECTIVE QUESTIONS.**

**Tick the correct answer in each of the following :**

**Question 1.**

**Solution:**

7a^{2} – 63b^{2} = 7 (a^{2 }– 9b^{2})

= 7 {(a)^{2} – (3b)^{2}}

= 7 (a – 3b) (a + 36) **(d)**

**Question 2.**

**Solution:**

2x – 32x^{3} = 2x (1 – 16x^{2})

= 2x {(1)^{2} – (4x)^{2}}

= 2x (1 – 4x) (1 + 4x)** (d)**

**Question 3.**

**Solution:**

x^{3} – 144x

= x (x^{2} – 144)

= x {(x)^{2} – (12)^{2}}

= x (x – 12) (x + 12) **(c)**

**Question 4.**

**Solution:**

2 – 50x^{2} = 2 (1 – 25x^{2})

= 2 {(1)^{2} – (5x)^{2}}

= 2 (1 – 5x) (1 + 5x)** (d)**

**Question 5.**

**Solution:**

a^{2} + bc + ab + ac

= a2 + ab + ac + bc

= a (a + b) + c (a + b)

= (a + b) (a + c) **(a)**

**Question 6.**

**Solution:**

pq^{2} + q (p – 1) – 1

= pq^{2} + 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:**

x^{2} – xz + xy – yz

= x (x – z) + y (x – z)

= (x – z) (x + y) **(c)**

**Question 10.**

**Solution:**

12m^{2} – 21

= 3 (4m^{2} – 9)

= 3 {(2m)^{2} – (3)^{2}}

= 3 (2m – 3) (2m + 3)** (c)**

**Question 11.**

**Solution:**

x^{3} – x

= x (x^{2} – 1)

= x (x – 1) (x + 1) **(d)**

**Question 12.**

**Solution:**

1 – 2ab – (a^{2} + b^{2})

= 1 – 2ab – a^{2} – b^{2}

= 1 – (a^{2} + b^{2} + 2ab)

= 1 – (a + b)^{2}

= (1 + a + b) (1 – a – b) **(c)**

**Question 13.**

**Solution:**

x^{2} + 6x + 8

= x^{2} + 4x + 2x + 8

{8 = 4 x 2, 6 = 4 + 2}

= x (x + 4) + 2 (x + 4)

= (x + 4) (x + 2) **(c)**

**Question 14.**

**Solution:**

x^{2} + 4x – 21

= x^{2} + 7x – 3x – 21

{ – 21 = + 7 x ( – 3), 4 = 7 – 3}

= x (x + 7) – 3 (x + 7)

= (x + 7) (x – 3) **(b)**

**Question 15.**

**Solution:**

y^{2} + 2y – 3

{ – 3 = 3 x ( – 1), 2 = 3 – 1}

= y^{2} + 3y – y – 3

= y (y + 3) – 1 (y + 3)

= (y + 3) (y – 1) **(a)**

**Question 16.**

**Solution:**

40 + 3x – x^{2}

= 40 + 8x – 5x -x^{2}

{40 = 8 x ( – 5), 3 = 8 – 5}

= 8(5 + x) – x(5 + x)

= (5 + x)(8 – x) **(c)**

**Question 17.**

**Solution:**

2x^{2} + 5x + 3

= 2x^{2} + 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:**

6a^{2} – 13a + 6

= 6a^{2} – 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:**

4z^{2} – 8z + 3

= 4z^{2} – 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 – 8y^{2}

= 3 + 24y – y – 8y^{2}

{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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