Chapter 4 Quadratic Functions and Factoring - 4.8 Use the Quadratic Formula and the Discriminant - 4.8 Exercises - Skill Practice - Page 296: 5

$$x=-4\pm \sqrt3i$$

We first check that the function is in the form $ax^2+bx+c$. Then, using the quadratic formula, we obtain: $$x=\frac{-b\pm \sqrt{b^2-4ac}}{2a}$$ $$x=\frac{-8\pm \sqrt{(8)^2-4(1)(19)}}{2(1)}$$ $$x=-4\pm \sqrt3i$$