Answer
See below
Work Step by Step
Add $4x^2$ to both sides:
$$8x^2=12\\
\rightarrow x^2=\frac{12}{8}=\frac{3}{2}\\
\rightarrow x= \pm \sqrt \frac{3}{2}$$
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.