## Functions Modeling Change: A Preparation for Calculus, 5th Edition

$P(4)-P(2)=-8$
To find $P(4)$, use $t=4$ with the formula. $$P(4)=170-4(4)=170-16=154$$ To find $P(2)$, use $t=2$ with the formula. $$P(2)=170-4(2)=170-8=162$$ Therefore, $$P(4)-P(2)=154-162=-8$$