Answer
$(2,2.5,2)$
Work Step by Step
In this case the transformation is linear if $T(v_1+v_2)=T(v_1)+T(v_2)$ and $T(av_1)=aT(v_1)$ for any $v_1,v_2$ in the domain and any $a$ scalar.
Hence $T(2,-1,1)=-1.5T(1,1,1)-0.5T(0,-1,2)+3.5T(1,0,1)=-1.5(2,0,-1)-0.5(-3,2,-1)+3.5(1,1,0)=(-3,0,1.5)+(1.5,-1,0.5)+(3.5,3.5,0)=(2,2.5,2)$