# How do you solve -4x^2+x+1=0 using the quadratic formula?

##### 1 Answer
Nov 13, 2014

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

By comparing with

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

we have

$\left\{\begin{matrix}a = - 4 \\ b = 1 \\ c = 1\end{matrix}\right.$

$x = \frac{- b \pm \sqrt{{b}^{2} - 4 a c}}{2 a}$

$= \frac{- 1 \pm \sqrt{{1}^{2} - 4 \cdot \left(- 4\right) \cdot 1}}{2 \cdot \left(- 4\right)}$

$= \frac{- 1 \pm \sqrt{17}}{- 8} = \frac{1 \pm \sqrt{17}}{8}$

Hence, the solutions are $x = \frac{1 \pm \sqrt{17}}{8}$.

I hope that this was helpful.