Answer
$$x=.5\pm.5\sqrt{67}i$$
Work Step by Step
When given the choice to use any method, the quadratic formula is a good choice because it will always work.
We first check that the function is in the form $ax^2+bx+c$. Then, using the quadratic formula, we obtain:
$$x=\frac{-b\pm \sqrt{b^2-4ac}}{2a}$$
$$x=\frac{5\pm \sqrt{(-5)^2-4(5)(85)}}{2(16)}$$
$$x=.5\pm.5\sqrt{67}i$$
