Use the square root property to solve the equation.
$x ^ { 2 } + 81 = 0$
A) $\{ 9 \}$
B) $\{ - 9,9 \}$
C) $\{ 6561 \}$
D) $\{ - 9 i , 9 i \}$

Question

Quizplus · Accepted Answer

To solve the equation $x^2 + 81 = 0$, we first isolate $x^2$ by subtracting 81 from both sides, giving $x^2 = -81$. Taking the square root of both sides gives $x = \pm \sqrt{-81}$. Since the square root of a negative number involves an imaginary unit $i$, we get $x = \pm 9i$, which corresponds to choice D.

Use the Square Root Property to Solve the Equation x2+81=0x ^ { 2 } + 81 = 0x2+81=0

Use the Square Root Property to Solve the Equation $x ^ { 2 } + 81 = 0$