Solve the equation using the quadratic formula. Check your solution. $z ^ { 2 } - z - 12 = 0$
A) 3, -4
B) 3
C) 4, -4
D) 4, -5
E) 3, -5

Question

Quizplus · Accepted Answer

The quadratic formula is $z = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$, where $a = 1$, $b = -1$, and $c = -12$. Plugging these values in gives $z = \frac{1 \pm \sqrt{1 + 48}}{2} = \frac{1 \pm \sqrt{49}}{2} = \frac{1 \pm 7}{2}$, which results in $z = 4$ and $z = -3$. Therefore, the correct solutions are 3 and -4.

Solve the Equation Using the Quadratic Formula z2−z−12=0z ^ { 2 } - z - 12 = 0z2−z−12=0

Solve the Equation Using the Quadratic Formula $z ^ { 2 } - z - 12 = 0$