Answer
(a) -5
(b) -1
Work Step by Step
We are given: $h(t)=-t+\frac{3}{2}$, $t=-4$, $t=1$
(a) We calculate the net change:
$h(1)-h(-4)=[-1+\displaystyle \frac{3}{2}]-[--4+\frac{3}{2}]=\frac{1}{2}-\frac{11}{2}=-5$
(b) We calculate the average rate of change:
$\frac{h(1)-h(-4)}{1--4}=\frac{-5}{5}=-1$