Let X and y be real numbers, and x1 − I + Y1 − 2I = 51 − 3I, then x + y=______ .

Let X and y be real numbers, and x1 − I + Y1 − 2I = 51 − 3I, then x + y=______ .

X1 − I + Y1 − 2I = x (1 + I) 2 + y (1 + 2I) 5 = (x2 + Y5) + (x2 + 2y5) I, and 51 − 3I = 5 (1 + 3I) 10 = 12 + 32i, so x2 + Y5 = 12 and X2 + 2y5 = 32, the solution is x = - 1, y = 5, so x + y = 4