x = y + 3
x^2 - y^2 = 63
(y + 3)^2 - y^2 = 63
(y + 3)(y + 3) - y^2 = 63
y^2 + 6y + 9 - y^2 = 63
6y + 9 = 63
6y = 54
y = 54/6
y = 9
x = y + 3
x = 9 + 3
x = 12
check...
x^2 - y^2 = 63 x = y + 3
12^2 - 9^2 = 63 12 = 9 + 3
144 - 81 = 63 12 = 12 (correct)
63 = 63 (correct)
ur 2 numbers are 9 and 12
