using the given: x = 5 + y square both sides x^2 = 25 + 10y + y^2 x^2 = 65 + y^2 65 + y^2 = 25 +10y +y^2
65 = 25 + 10y 40 = 10y 4 = y y = 4
x - y = 5 x - (4) = 5 x = 9
check, does 9^2 - 4^2 = 65? yes, 81 - 16 = 65
x = 4, y = 9