# How do you solve using the quadratic formula x^2-7x-8=0?

Nov 13, 2016

$x = 8$ and $x = - 1$

#### Explanation:

This quadratic can be factored to:

$\left(x - 8\right) \left(x + 1\right) = 0$

Solving for $\left(x - 8\right)$ gives:

$\frac{\left(x - 8\right) \left(x + 1\right)}{\left(x + 1\right)} = \frac{0}{x + 1}$

$x - 8 = 0$

$x - 8 + 8 = 0 + 8$

$x = 8$

Solving for $\left(x + 1\right)$ gives:

$\frac{\left(x - 8\right) \left(x + 1\right)}{\left(x - 8\right)} = \frac{0}{x - 8}$

$x + 1 = 0$

$x + 1 - 1 = 0 - 1$

$x = - 1$