Use the quadratic formula to solve the equation.
-$$( x + 8 ) ( x - 1 ) = 9$$
A) $\left\{ \frac { - 7 - 3 \sqrt { 13 } } { 2 } , \frac { - 7 + 3 \sqrt { 13 } } { 2 } \right\}$
B) $\left\{ \frac { - 7 - 3 i \sqrt { 13 } } { 2 } , \frac { - 7 + 3 i \sqrt { 13 } } { 2 } \right\}$
C) $\left\{ \frac { 7 - 3 i \sqrt { 13 } } { 2 } , \frac { 7 + 3 i \sqrt { 13 } } { 2 } \right\}$
D) $\left\{ \frac { 7 - 3 \sqrt { 13 } } { 2 } , \frac { 7 + 3 \sqrt { 13 } } { 2 } \right\}$

Question

Quizplus · Accepted Answer

First, expand and rearrange the given equation to standard form: $x^2 + 7x - 9 = 0$. Applying the quadratic formula, $\frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$, with $a = 1$, $b = 7$, and $c = -9$, yields roots $\frac{-7 \pm \sqrt{49 + 36}}{2}$, which simplifies to $\frac{-7 \pm 3\sqrt{13}}{2}$.

Use the Quadratic Formula to Solve the Equation (x+8)(x−1)=9( x + 8 ) ( x - 1 ) = 9(x+8)(x−1)=9

Use the Quadratic Formula to Solve the Equation $( x + 8 ) ( x - 1 ) = 9$