Question

Write the following as a product of factor: 

x(2x + 5) – 25

Answer 1

Given expression: x(2x + 5) – 25 = 2x² + 5x – 25

We have to find two numbers whose sum is 5 and whose product is –50.

These numbers are 10 and –5.

Now, using middle term factorisation method,

2x² + 5x – 25

= 2x² + 10x – 5x – 25

= 2x(x + 5) – (5x + 5)

= (x + 5) (2x – 5)

The factorisation result is (x + 5) (2x – 5).