Center = (h,k) = (2,-3) \ \
a = 4 \ \
Vertices are \ \
V1 = (h-a , k) = (2-4 , 3) = (-2,-3) \ \
V2 = (h-a , k) = (2+4, 3) = (6,-3)
The solution is " (2, 3) ; (6, 3) ".