# How do you solve x^2 + 3 = 9x using the quadratic formula?

May 11, 2016

$x = \frac{9 \pm \sqrt{69}}{2}$
$y = {x}^{2} - 9 x + 3 = 0.$
$D = {d}^{2} = {b}^{2} - 4 a c = 81 - 12 = 69$ --> $d = \pm \sqrt{69}$.
$x = - \frac{b}{2 a} \pm \frac{d}{2 a} = \frac{9}{2} \pm \frac{\sqrt{69}}{2} = \frac{9 \pm \sqrt{69}}{2}$