Question

Factorise the following:

2x² – 7x – 39

Answer 1

The given expression is 2x² – 7x – 39

Here, 2 × (–39) = –78

So, we split –7 into parts whose sum is –7 and product –78

Clearly, (–13) + 6 = –7 and (–13) × 6 = –78

∴ 2x² – 7x – 39 = 2x² – 13x + 6x – 39

= (2x – 13) (x + 3)

Hence, (2x² – 7x – 39) = (2x – 13) (x + 3).