Solve the equation.
-$$x ^ { 2 } - 4 x + 20 = 0$$
A) $2 \pm 4 \mathrm { i }$
B) $- 2 \pm 4 i$
C) $6 , - 2$
D) $4 \pm 8 \mathrm { i }$

Question

Quizplus · Accepted Answer

This equation can be solved using the quadratic formula, $$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$$, where $a = 1$, $b = -4$, and $c = 20$. Plugging these values in, we get $$x = \frac{4 \pm \sqrt{(-4)^2 - 4 \cdot 1 \cdot 20}}{2 \cdot 1} = \frac{4 \pm \sqrt{16 - 80}}{2} = \frac{4 \pm \sqrt{-64}}{2} = 2 \pm 4i$$.

Solve the Equation x2−4x+20=0x ^ { 2 } - 4 x + 20 = 0x2−4x+20=0

Solve the Equation $x ^ { 2 } - 4 x + 20 = 0$