Solve the equation. $- x ^ { 2 } - 7 x + 8 = 0$
A) { 1, -8 }
B) { 1, 8 }
C) { -1, -8 }
D) { -1, 8 }

Question

Quizplus · Accepted Answer

This quadratic equation can be solved by factoring, completing the square, or using the quadratic formula. The quadratic formula is $x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$, where $a = -1$, $b = -7$, and $c = 8$. Substituting these values gives $x = \frac{7 \pm \sqrt{(-7)^2 - 4(-1)(8)}}{2(-1)} = \frac{7 \pm \sqrt{49 + 32}}{-2} = \frac{7 \pm \sqrt{81}}{-2} = \frac{7 \pm 9}{-2}$, which results in $x = 1$ and $x = -8$. Therefore, the correct answer is {1, -8}.

Solve the Equation −x2−7x+8=0- x ^ { 2 } - 7 x + 8 = 0−x2−7x+8=0

Solve the Equation $- x ^ { 2 } - 7 x + 8 = 0$