Integers = …, -4, -3, -2, -1, 0, 1, 2, 3, 4, …
x = -4, x2 = (-4)2 = 16 > 9
x = -3, x2 = (-3)2 = 9
x = -2, x2 = (-2)2 = 4
x = -1, x2 = (-1)2 = 1
x = 0, x2 = (0)2 = 0

x = 1, x2 = (1)2 = 1
x = 2, x2 = (2)2 = 4
x = 3, x2 = (3)2 = 9
x = 4, x2 = (4)2 = 16
The elements of this set are -3, -2, -1, 0, 1, 2, 3
So, D = {-3, -2, -1, 0, 1, 2, 3}