You have 16 units in x-direction from -6 to 10.
of 16 is 12; so, you add 12 to -6 and get new x-coordinate of 6.
You have 12 units in y-direction from -3 to 9.
of 12 is 9; so, you add 9 to -3 and get new y-coordinate of 6.
Thus the point you want is (6,6).