(1) 5 + iy = x + i3 In order for complex numbers to be equal the real parts have to be equal and the imaginary parts have to be equal. For (1) we have (2) 5 = x for the real parts, therefore (3) x = 5 And for the imaginary parts we have (4) iy = i3, therefore (5) y = 3 Answer: x = 5 and y = 3.