# How do you solve x^2 – 4x – 5 = 0 using the quadratic formula?

Jun 7, 2016

#### Answer:

$x = 5 , - 1$

#### Explanation:

Use the quadratic formula for : $a {x}^{2} + b x + c$

$x = \frac{- b \pm \sqrt{{b}^{2} - 4 a c}}{2 a}$

 x = (( 4 +- sqrt( 16- 4(1)(-5))) /(2*(1))

$x = \left(\frac{4 \pm \sqrt{36}}{2}\right)$

$x = 2 \pm 3$

$x = 5 , - 1$