Answer
$x=0.15$ or $x=7.85$
Work Step by Step
$-x^2+8x+4=5$
$-x^2+8x-1=0$
Use the quadratic formula.
$x=\frac{-(8) \pm \sqrt (8)^2-4.(-1).(-1)}{2.(-1)}$
$x=\frac{-8 \pm 2\sqrt 15}{-2}$
$x=\frac{-8 \pm 7.7}{-2}$
$x=\frac{-8+7.7}{-2}$ or $x=\frac{-8- 7.7}{-2}$
$x=0.15$ or $x=7.85$
