Solve by completing the square.
-$$x ^ { 2 } = 7 - 8 x$$
A) $- 4 \pm 2 \sqrt { 23 }$
B) $4 + \sqrt { 23 }$
C) $- 4 \pm \sqrt { 23 }$
D) $- 1 \pm \sqrt { 23 }$

Question

Quizplus · Accepted Answer

To solve by completing the square, rewrite the equation as $x^2 + 8x = 7$. Add $(8/2)^2 = 16$ to both sides to get $x^2 + 8x + 16 = 23$. This can be written as $(x + 4)^2 = 23$. Taking the square root of both sides gives $x + 4 = \pm \sqrt{23}$, so $x = -4 \pm \sqrt{23}$.

Solve by Completing the Square x2=7−8xx ^ { 2 } = 7 - 8 xx2=7−8x

Solve by Completing the Square $x ^ { 2 } = 7 - 8 x$