# How do you factor x^2 + x - 6?

Jun 4, 2015

Notice that $3 \times 2 = 6$ and $3 - 2 = 1$.

So

$\left(x + 3\right) \left(x - 2\right) = {x}^{2} + 3 x - 2 x - \left(3 \times 2\right)$

$= {x}^{2} + \left(3 - 2\right) x - \left(3 \times 2\right) = {x}^{2} + x - 6$

This is an instance of the general form:

$\left(x + a\right) \left(x - b\right) = {x}^{2} + \left(a - b\right) x - a b$