Find the unknown numbers in the description. Three times a number is between - 18 and 18. The solution set is

So 3 times a number is between - 18 and 18

between means it cannot be - 18 or 18 so

3 times x=3x

x=unknown

3x

< less than

>greater than

if it is between - 18 and 18 then the number is >-18 and <18 so

-18<3x and

18>3x

divide both equations by 3

-6
6>x

combine

-6
solution set = (x|-6