Work Step by Step
Use the formula $(a-b)(a+b)=a^2-b^2$ with $a=2y$ and $b=7$ to obtain: $=(2y)^2-7^2 \\=4y^2-49$
You can help us out by revising, improving and updating this answer.Update this answer
After 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.