# How do you solve x^2 = 5x + 8 using the quadratic formula?

Jul 19, 2016

$\frac{5 \pm \sqrt{57}}{2}$
$y = {x}^{2} - 5 x - 8 = 0$
$D = {d}^{2} = {b}^{2} - 4 a c = 25 + 32 = 57$ --> $d = \pm \sqrt{57}$
$x = - \frac{b}{2 a} \pm \frac{d}{2 a} = \frac{5}{2} \pm \frac{\sqrt{57}}{2} = \frac{5 \pm \sqrt{57}}{2}$