Answer
$(0,-6,8)$
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 $T(2,-4,1)=2T(1,0,0)-4T(0,1,0)+T(0,0,1)=2(2,4,-1)-4(1,3,-2)+(0,-2,2)=(4,8,-2)-(4,12,-8)+(0,-2,2)=(0,-6,8)$