NCERT Solutions For Class 8 Maths Chapter 9,Algebraic Expressions And Identities, Exercise 9.5

NCERT Solutions Class 8 Chapter 9, Algebraic Expressions and Identities, Ex.9.5

Class 8, Maths, Chapter 9, Exercise 9.5, Solutions

Q.1.Use a suitable identity to get each of the following products.

(i) (x+3) (x+3)

(ii) (2y+5) (2y+5)

(iii) (2a –7) (2a–7)

(iv) $\left( 3a-\frac{1}{2} \right)\left( 3a-\frac{1}{2} \right)$

(v) (1.1m – 0.4) (1.1m + 0.4)

(vi) (a2+b2) (–a2+b2)

(vii) (6x – 7) (6x + 7)

(viii) (– a + c) (– a + c)

(ix) $\left( \frac{x}{2}+\frac{3y}{4} \right)\left( \frac{x}{2}+\frac{3y}{4} \right)$

(x) (7a – 9b) (7a – 9b)

NCERT Solutions Class 8 Chapter 9, Algebraic Expressions and Identities, Ex.9.5 Q.1 (i-v)

NCERT Solutions Class 8 Chapter 9, Algebraic Expressions and Identities, Ex.9.5 Q.1 (vi-x)

Q.2. Use the identity (x+a) (x+b)=x2 +(a+b)x + ab to find the following products.

(i) (x+3) (x+7)

(ii) (4x+5) (4x+1)

(iii) (4x–5) (4x –1)

(iv) (4x+5) (4x–1)

(v) (2x+5y) (2x+3y)

(vi) (2a2+9) (2a2+5)

(vii) (xyz – 4) (xyz –2)

NCERT Solutions Class 8 Chapter 9, Algebraic Expressions and Identities, Ex.9.5 Q.2 (i-iv) NCERT Solutions Class 8 Chapter 9, Algebraic Expressions and Identities, Ex.9.5 Q.2 (v-vii) 

Q.3. Find the following squares by using the identities.

(i) (b –7)2

(ii) (xy + 3z)2

(iii) (6x2 – 5y)

(iv) ${\left( \frac{2}{3}m+\frac{3}{2}n \right)}^{2}$

(v) (0.4p – 0.5q)2

(vi) (2xy+5y)2

NCERT Solutions Class 8 Chapter 9, Algebraic Expressions and Identities, Ex.9.5 Q.3 (i-iii)

NCERT Solutions Class 8 Chapter 9, Algebraic Expressions and Identities, Ex.9.5 Q.3 (iv-vi)

Q.4. Simplify.

(i) (a2 – b2)2

(ii) (2x + 5)2 – (2x– 5)2

(iii) (7m – 8n)2 + (7m+8n)2

(iv) (4m+5n)2 + (5m + 4n)2

(v) (2.5p – 1.5q)2 – (1.5p – 2.5q)2

(vi) (ab + bc)2 – 2ab2c 

(vii) (m2 – n2m)2 + 2m3n2

NCERT Solutions Class 8 Chapter 9, Algebraic Expressions and Identities, Ex.9.5 Q.4 (i-iv) NCERT Solutions Class 8 Chapter 9, Algebraic Expressions and Identities, Ex.9.5 Q.4 (v) NCERT Solutions Class 8 Chapter 9, Algebraic Expressions and Identities, Ex.9.5 Q.4 (vi-vii)

Q.5. Show that.

(i) (3x+7)2– 84x = (3x – 7)2

(ii) (9p – 5q)2+180pq = (9p + 5q)2

(iii) ${{\left( \frac{4}{3}m-\frac{3}{4}n \right)}^{2}}+2mn=\frac{16}{9}{{m}^{2}}+\frac{9}{16}{{n}^{2}}$

(iv) (4pq + 3q)2 – (4pq – 3q)2= 48pq2

(v) (a–b) (a+b)+(b – c) (b+c)+(c–a) (c+a) = 0

NCERT Solutions Class 8 Chapter 9, Algebraic Expressions and Identities, Ex.9.5 Q.5 (i-iii) NCERT Solutions Class 8 Chapter 9, Algebraic Expressions and Identities, Ex.9.5 Q.5 (iv-v)

Q.6. Using identities, evaluate.

(i) 712

(ii) 992

(iii) 1022

(iv) 9982

(v) 5.22

 (vi) 297 × 303

(vii) 78 × 82

(viii) 8.92

(ix) 10.5 × 9.5

NCERT Solutions Class 8 Chapter 9, Algebraic Expressions and Identities, Ex.9.5 Q.6 (i-v)

NCERT Solutions Class 8 Chapter 9, Algebraic Expressions and Identities, Ex.9.5 Q.6 (vi-ix)

Q.7. Using a2– b2 =(a + b) (a – b), find

(i) 512– 492

(ii) (1.02)2 – (0.98)2

(iii) 1532–1472

(iv) 12.12 – 7.92

NCERT Solutions Class 8 Chapter 9, Algebraic Expressions and Identities, Ex.9.5 Q.7

Q.8. Using (x+a) (x+ b) = x2 + (a+b)x + ab, find

(i) 103 × 104

(ii) 5.1 × 5.2

(iii) 103 × 98

(iv) 9.7 × 9.8

NCERT Solutions Class 8 Chapter 9, Algebraic Expressions and Identities, Ex.9.5 Q.8

NCERT Solutions For Class 8 Maths Chapter 9, Algebraic Expressions and Identities (All Exercises)

Class 8, Maths, Chapter 9, Algebraic Expressions and Identities 

Class 8, Maths, Chapter 9, Algebraic Expressions and Identities , Exercise 9.1 

Class 8, Maths, Chapter 9, Algebraic Expressions and Identities , Exercise 9.2 

Class 8, Maths, Chapter 9, Algebraic Expressions and Identities , Exercise 9.3 

Class 8, Maths, Chapter 9, Algebraic Expressions and Identities , Exercise 9.4 

Class 8, Maths, Chapter 9, Algebraic Expressions and Identities , Exercise 9.5 ← You are here