# How do you find all zeros of the function f(x) = x² – 9x – 70?

Aug 11, 2018

$f \left(x\right)$ has zeros $x = 14$ and $x = - 5$

#### Explanation:

Given:

$f \left(x\right) = {x}^{2} - 9 x - 70$

Find two factors of $70$ which differ by $9$.

The pair $14 , 5$ works.

Hence we find:

$f \left(x\right) = {x}^{2} - 9 x - 70 = \left(x - 14\right) \left(x + 5\right)$

So $f \left(x\right)$ has zeros $x = 14$ and $x = - 5$