Calculus 10th Edition

The absolute maximum is $4$ and the absolute minimum is $1$ over the specified interval.
$f'(x)=-1$ Since $f'(x)$ is never $0,$and is defined for all x in the interval, the maximum and minimum have to occur at the endpoints of the interval: $f(-1)=4.$ $f(2)=1.$ The absolute maximum is $4$ and the absolute minimum is $1$ over the specified interval.