Answer
$x=3.16$ and $x=-3.16$
Work Step by Step
The given equation is
$\Rightarrow 2x^2-9=11$
Add $9$ to each side.
$\Rightarrow 2x^2-9+9=11+9$
Simplify.
$\Rightarrow 2x^2=20$
Divide each side by $2$.
$\Rightarrow \frac{2x^2}{2}=\frac{20}{2}$
Simplify.
$\Rightarrow x^2=10$
Take the square root of each side.
$\Rightarrow x=\pm \sqrt {10}$
Use a calculator.
$\Rightarrow x=\pm 3.16$
Hence, the solutions are $x=3.16$ and $x=-3.16$.
