We begin by factoring the parentheses completely:
5u(v+7w)+7s(-v-7w)
we factor the minus out of the second parenthesis.
5u(v+7w)-7s(v+7w)
now we factor (v+7w) out
(v+7w)(5u×1-7s×1)
(v+7w)(5u-7s)
answer.
the identity factorized entirely is:
(v+7w)(5u-7s)
