Write the following sets in roster from:
Question:

Write the following sets in roster from

D = {x : x is an integer, x2 ≤ 9}

Solution:

Integers = …, -4, -3, -2, -1, 0, 1, 2, 3, 4, …

$x=-4, x^{2}=(-4)^{2}=16>9$

$x=-3, x^{2}=(-3)^{2}=9$

$x=-2, x^{2}=(-2)^{2}=4$

$x=-1, x^{2}=(-1)^{2}=1$

$x=0, x^{2}=(0)^{2}=0$

$x=1, x^{2}=(1)^{2}=1$

$x=2, x^{2}=(2)^{2}=4$

$x=3, x^{2}=(3)^{2}=9$

$x=4, x^{2}=(4)^{2}=16$

The elements of this set are -3, -2, -1, 0, 1, 2, 3

So, D = {-3, -2, -1, 0, 1, 2, 3}