Answer
$x=4$ and $x=-4$
Work Step by Step
The given equation is
$\Rightarrow 4x^2=64$
Divide each side by $4$.
$\Rightarrow \frac{4x^2}{4}=\frac{64}{4}$
Simplify.
$\Rightarrow x^2=16$
Take the square root of each side.
$\Rightarrow x=\pm \sqrt {16}$
Use a calculator.
$\Rightarrow x=\pm 4$
Hence, the solutions are $x=4$ and $x=-4$.
