Question

Find the value of the following expression for the given values.

n2−m2​; n=−3​, and m=-7

Answer 1

$$n^2-m^2=(-3)^2-(-7)^2=9-49=-40$$

$$n^2-m^2=(n-m)(n+m)$$

$$=(-3-(-7))(-3+(-7))=4(-10)=-40$$