Question

Which binomial is a factor of x^2 + 2x - 15

Answer 1

(x−5)(x+3)

Explanation:

To factorise, we firstly need two brackets, each containing an x.

(x)(x)

This creates the x2 term.

Now we need to get the rest of the terms. To do this, we need two factors of −15 which will add/subtract to give us +2

The two factors that do this are −3 and 5, as −3+5=2

∴(x−3)(x+5)

You can check by expanding it out.