Answer
See below.
Work Step by Step
$(A+B)^2=A^2+2AB+B^2$. The square of a binomial sum is the square of the first term plus twice the product of terms plus the square of the last term.
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.