Answer:
Step-by-step explanation:
x = 1 + 3i
x^2 = (1 + 3i)(1 + 3i)
x^2 = 1 + 6i - 9 = -8 + 6i
By a similar method
y = (x - i)
y^2 = x^2 - 2i*x + i^2
y^2 = x^2 - 2ix - 1
y^2 = -8+6i - 2i(1 + 3i) -1
y^2 = -8+6i -2i - 6i - 1
y^2 = -8 - 2i - 1
y^2 = - 9 - 2i
x^2 - y^2 = -8 + 6i - (9 - 2i)
x^2 - y^2 = -8 + 6i - 9 + 2i
x^2 - y^2 = -17 + 8i