Answer
a) The rate of change is $-0.5$.
b) $f(x)=-0.5x+2$.
Work Step by Step
a) The rate of change (slope) can be calculated from two points:
$\frac{f(y)-f(x)}{y-x}=\frac{f(1)-f(0)}{1-0}=\frac{1-1.5}{1-0}=\frac{-0.5}{1}=-0.5$.
b) $f(x)=2$ at $x=0$, so the y-intercept is $b=2$. Hence, we have: $f(x)=-0.5x+2$.
