Answer
$(8q+9)(8q-9)$
Work Step by Step
$64q^{2}-81=$
...write each term as a square.
$=(8q)^{2}-9^{2}$
...factor using the rule for a difference of two squares.
($a^{2}-b^{2}=(a+b)(a-b),\ a=8q,\ b=9$)
$=(8q+9)(8q-9)$
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.