According to the given data we have the following:
Triangle CDE with vertices C(2,-1), D(7,-4),E(4,-6)
(x,y)=(x-3,y+8)
In order to calculate the coordinates for C, D and E we would plug in (x-3,y+8) the values of each of the vertices and then proceed with the calculation:
So coordinates for C=(2-3,-1+8)=C=(-1,7)
coordinates for D=(7-3,-4+8)=D=(4,-4)
coordinates for E=(4-3,-6+8)=E=(1,-2)