What is the value of z so that-9 and 9 are both solutions of x^2+z=103?

a) -22
b) 3
c) 22
d 184

If the sol'ns are -9 and 9, then we can use this to form our eq'n:
(x - 9)(x + 9) = 0
x^2 - 81 = 0
so...
x^2 + z - 103 = x^2 -81
z - 103 = -81
z = -81 + 103
z = 22

Where is the problems