Answer
(a) $1700J$
(b) $-1700J$
Work Step by Step
(a) We can find the required work done as follows:
$\vec d=\vec v t$
$\implies \vec d=(4.1)(25)=102.5m\hat x$
Now $W=F_xd_x$
We plug in the known values to obtain:
$W=(17)(102.5)=1700J\approx 1700J$
(b) We can find the required done as follows:
$W=Fd_x$
We plug in the known values to obtain:
$W=(-17N)(102.5m)$
$W=-1742.5J\approx-1700J$