# How do I use the quadratic formula to solve 4x^2+x-1=0?

Sep 30, 2014

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

$4 {x}^{2} + 1 x - 1 = 0$

$a = 4 , b = 1 , c = - 1$

$x = \frac{- b \pm \sqrt{{b}^{2} - 4 a c}}{2 a}$
$x = \frac{- \left(1\right) \pm \sqrt{{\left(1\right)}^{2} - 4 \left(4\right) \left(- 1\right)}}{2 \left(4\right)}$
$x = \frac{- 1 \pm \sqrt{1 + 16}}{8}$
$x = \frac{- 1 \pm \sqrt{17}}{8}$