Question

factor the expression. r^2 – 49 a. (r – 7)(r 9) b. (r 7)(r 7) c. (r – 7)(r 7) d. (r – 7)(r – 7)

Answer 1

$r^2-49=r^2-7^2\\\\/use\ a^2-b^2=(a-b)(a+b)/\\\\=\boxed{(r-7)(r+7)}$