Question

Find the product. (7 q - 5)(7 q + 5)
49q^2 - 10q - 25
49q^2 + 10q - 25
49q^2 - 25

Answer 1

$Use\ (a-b)(a+b)=a^2-b^2.\\\\(7q-5)(7q+5)=(7q)^2-5^2=\boxed{49q^2-25}$