## College Algebra (6th Edition)

$49x^2-9y^2$
$$(7x+3y)(7x-3y)$$ The product of the sum and the difference of two terms can be found using this formula: $(a+b)(a-b) = a^2-b^2$. $$=(7x)^2-(3y)^2$$ $$=49x^2-9y^2$$