## Calculus with Applications (10th Edition)

$(z+7y)^2$
RECALL: $a^2 + 2ab + b^2=(a+b)^2$ The given trinomial can be written as: $=z^2 + 2(z)(7y) + (7y)^2$ Factor the trinomial using the formula above with $a=z$ and $b=7y$ to have: $=(z+7y)^2$