on the 2d graph there are 4 directions up down left and right
up = +y
down = -y
left = -x
right = +x
since you want to move 8 units left and 6 units down we can subtract 8 from the first coordinate and 5 from the second coordinate
8-8 = 0 and 13-6 = 7
the desired point is (0,7)