# How do you factor the expression x^2 + 6x – 7?

Dec 31, 2015

You use the sum-product method.

#### Explanation:

This means that you factor $- 7$ and see what factors add up to the sum of $+ 6$.

The only ways you can factor:
$- 7 = \left(- 1\right) \left(+ 7\right) = \left(+ 1\right) \left(- 7\right)$

Only the factors $- 1$ and $+ 7$ add up to $+ 6$

So you get: $= \left(x - 1\right) \left(x + 7\right)$