Answer
$x = -2$ or $x = -6$
Work Step by Step
The quadratic formula is given as $x = \dfrac{-b ± \sqrt {b^2 - 4ac}}{2a}$, where $a$ is the coefficient of the $x^2$ term, $b$ is the coefficient of the $x$-term, and $c$ is the constant term.
Plug in the values from this exercise into this formula:
$x = \dfrac{-8 ± \sqrt {8^2 - 4(1)(12)}}{2(1)}$
Evaluate the exponent first:
$x = \dfrac{-8 ± \sqrt {64 - 4(1)(12)}}{2(1)}$
$x = \dfrac{-8 ± \sqrt {64 - 48}}{2}$
Simplify the radicand:
$x = \dfrac{-8 ± \sqrt {16}}{2}$
Take the square root:
$x = \dfrac{-8 ± 4}{2}$
Add or subtract terms in the numerator:
$x = \dfrac{-4}{2}\quad$ or $\quad x = \dfrac{-12}{2}$
Simplify the fractions:
$x = -2$ or $x = -6$