Question

How to factorise by grouping for 7a, d and h

Answer 1

You have to take out the common terms :

Question A,

`{x}^(2) + 4x + ax + 4a`

`= x(x + 4) + a(x + 4)`

`= (x + a)(x + 4)`

Question D,

`{x}^(2) + 2x - ax - 2a`

`= x(x + 2) - a(x + 2)`

`= (x - a)(x + 2)`

Question H,

`{x}^(2) - 2bx - 5x + 10b`

`= x(x - 2b) - 5(x - 2b)`

`= (x - 5)(x - 2b)`

Answer 2

Explanation:

7a

x2 + 4x + ax + 4a

x2 + ax + 4x + 4a

x (x + a) + 4 (x + a)

:(x + 4)(x+a)

7d

x2+2x-ax-2a

x2-ax+2x-2a

x (x-a)+2 (x-a)

:(x+2)(x-a)

7h

x2-2bx-5x+10b

x2-5x-2bx+10b

x (x-5)-2b(x-5)

:(x-2b)(x-5)