# How do you solve the quadratic using the quadratic formula given x^2=-3x+40?

Sep 23, 2016

$x = - 8 , 5$

#### Explanation:

We have: ${x}^{2} = - 3 x + 40$

$\implies {x}^{2} + 3 x - 40 = 0$

$\implies x = \frac{- 3 \pm \sqrt{{3}^{2} - 4 \left(1\right) \left(- 40\right)}}{2 \left(1\right)}$

$\implies x = \frac{- 3 \pm \sqrt{169}}{2}$

$\implies x = \frac{- 3 \pm 13}{2}$

$\implies x = - 8 , 5$

Therefore, the solutions to the equation are $x = - 8$ and $x = 5$.