Answer
(a) $W = -6.0 J$
(b) $W=12.0 J$
Work Step by Step
(a) $W =\vec F . \Delta\vec r $
$W= ( -3.0 \vec i + 6.0 \vec j)N.(2.0 \vec i )m$
$ W = (-3.0 × 2)J +( 6.0×0)J $
$W = -6.0 J$
(b) $W =\vec F . \Delta\vec r $
$W= (-3.0 \vec i + 6.0\vec j)N.( 2.0\vec j )m$
$ W =( -3×0 )J+( 6.0×2.0 ) J $
$W=12.0 J$