Answer
$y=±2\sqrt5$
Work Step by Step
$y^2=20 \\ y=± \sqrt{20} = ±2\sqrt{5}$
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.