# How do you solve x^2+8x-5=0?

May 22, 2015

For a quadratic equation of the form $a {x}^{2} + b x + c = 0$
the solutions are given by the quadratic formula
$x = \frac{- b \pm \sqrt{{b}^{2} - 4 a c}}{2 a}$

For ${x}^{2} + 8 x - 5 = 0$
this becomes

$\frac{- 8 \pm \sqrt{64 + 20}}{2}$

$= - 4 \pm \sqrt{21}$