Algebra 1: Common Core (15th Edition)

Published by Prentice Hall
ISBN 10: 0133281140
ISBN 13: 978-0-13328-114-9

Chapter 8 - Polynomials and Factoring - 8-4 Multiplying Soecial Cases - Practice and Problem-Solving Exercises - Page 508: 50


The middle term should be $-2(21a)$. Result: $9a^{2}-42a+49$.

Work Step by Step

The middle term should be $-2(21a) $because $(a-b)^{2}=a^{2}\color{red}{-2ab}+b^{2}$, $(3a-7)^{2}=9a^{2}-42a+49$.
Update this answer!

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.