# How do I use the quadratic formula to solve f(x) = x^2 + 3x - 7?

Sep 30, 2014

$a {x}^{2} + b x + c = 0$

${x}^{2} + 3 x - 7 = 0$

$a = 1 , b = 3 , c = - 7$

$x = \frac{- b \pm \sqrt{{b}^{2} - 4 a c}}{2 a}$
$x = \frac{- \left(3\right) \pm \sqrt{{\left(3\right)}^{2} - 4 \left(1\right) \left(- 7\right)}}{2 \left(1\right)}$
$x = \frac{- 3 \pm \sqrt{9 + 28}}{2}$
$x = \frac{- 3 \pm \sqrt{37}}{2}$