Page 46 - Concepts of Reasoning-8

Worksheet-7.3

Factorisation of Quadratic Trinomials and Division of Polynomials

1. Write the missing steps in each of the following :
2
a. Factorise 9x + 14x + 5 + ______

Step : 1 ac = 9 × 5 =

Step : 2 The factors of ac :
2
Step : 3 Rearrange the terms 9x + 14x + 5
2
= 9x + + 5
= 9x ( ) + 5 ( )
Step : 4 Take common,
2
9x + 14x + 5 =

2
b. Factorise 6x + 16x + 8 = ______

Step : 1 ac = 6 × 8 =

Step : 2 The factors of ac :

2
Step : 3 Rearrange the terms 6x + 16x + 8
2
= 6x + + 8
= 6x ( ) + 4 ( )
Step : 4 Take common,
2
6x + 16x + 8 =
2. Divide the following expressions and match with their answers :

3 5
7 6
a. x y ÷ x y i. (x + 8)
5
4
5
b. 49x ÷ 7x ii. x y
2
c. (6x + 18x) ÷ (x + 3) iii. 7
2
d. (x + 3x – 40) ÷ (x + 5) iv. 6x

46 Reasoning - 8