# How do I solve the formula kx^2 + 8x + 4 = 0 for x?

Oct 19, 2014

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

$x = \frac{- 8 \pm \sqrt{{8}^{2} - 4 \cdot k \cdot 4}}{2 k} = \frac{- 8 \pm \sqrt{64 - 16 k}}{2 k}$

by factoring $4$ out of the square-root,

$= \frac{- 8 \pm 4 \sqrt{4 - k}}{2 k}$

by dividing the numerator and the denominator by $2$,

$= \frac{- 4 \pm 2 \sqrt{4 - k}}{k}$

I hope that this was helpful.