Answer
$(6x-7)(6x-7)$
Work Step by Step
Factor by using trial and error to get two terms that equal the first term times third term when multiplied and also add up to the second term. Then replace the middle term with those two terms and group all the terms. Then pull out the greatest common factors of each group to factor completely.
$36x^2-84x+49$
$36x^2-42x-42x+49$
$6x(6x-7)-7(6x-7)$
$(6x-7)(6x-7)$
