Class 7 Mathematics Exercise 4.2 Full Solution

(1) Solution:-

45a⁴÷ 9a²

= 45a⁴/9a²

= 5a²

(2) Solution:-

-24a⁵÷ 3a²

= – 24a⁵/3a²

= -8a³

(3) Solution:-

30a⁴ x³ ÷ 6a² x

= – 30a⁴ x³ / 6a² x

= -5 a² x²

(4) Solution:- – 28 x⁴ y³ z² ÷ 4x y z

= – 28 x⁴ y³ z² /4x y² z

= – 7 x³ y z

(5) Solution:-

-36a³ z³ y² ÷ (-4ayz)

= – 36a³ z³ y²/- 4ayz

= 9a²y z²

(6) Solution:-

– 22 x³ y²z÷ – 2xyz

= – 22 x³ y² z/ – 2xy z

= 11 x² y

(7) Solution:-

(3a³ b³– 2a² b³) ÷ a²b²

= 3a³b² – 2a² b² /a² b²

= 3 a³ b² /a² b² – 2a² b³ /a² b²

= 3a- 2b

(8) Solution:-

(36 x⁴ y³ + 9x⁵ y²) ÷ 9xy

= 36 x⁴ y³ /9 x y+ 9x⁵ y² /9xy

= 4 x³ y² + x⁴ y

(9) Solution:-

(a³ b⁴– 3a⁷ b⁷) ÷ – a³ b³

= a³ b⁴ / a³ b³ – 3a⁷ b⁷/ a³ b³

= b- 3a⁴ b⁴

(10) Solution:-

(6a b -9a b) V 3a b

= 6a b/3a b – 9a b/3a b

= 2a b- 3a b

(11) Solution:-

(15x³ y³ + 12x³ y²– 1 x⁵ y³ ) ÷ 3x² y²

= 15x³ y³/ 3x² y² + 12x³ y² / 3x² y² – 12x³ y²/ 3x² y²

= 5xy+ 4x – 4x³ y

(12) Solution:-

(6x⁸ y⁶ z- 4x⁴ y³ z² + 2x²y²z²) ÷ 2 x² y² z

= 6x⁸ y⁶ z/ 2 x² y² z – 4x⁴ y³ z²/ 2 x² y² z+2x²y²z² /2 x² y² z

= 3 x⁶ y⁴ – 2 x²z + z

(13) Solution:-

(24a² b² c- 15a⁴ b⁴ c⁴ – 9a² b⁶ c²) ÷ (-3ab²)

= 24a² b² c /-3ab²– 15a⁴ b⁴ c⁴ /-3ab²– 9a² b⁶ c²/ -3ab²

= – 8a c + 5a³ b² c⁴+ 3ab⁴ c²

(14) Solution:-

(a³ b³ + 2a² b³) ÷ (a+2b)

= a³ b³/ a+2b + 2a² b³/ a+2b

= a² b²

(15) Solution:-

(6x² +x-2) ÷ (2x -1)

= (6x² +x-2)/(2x-1)

= 3x+2