Solve for y.
[tex]y^2 - 144 = 0[/tex]
[tex]y^2 = 144[/tex] <-- Add 144 to each side
[tex]y = 12[/tex] <-- Take the square root of both sides
Because of the fact that squaring a negative number will result in a positive number, both 12 and -12 are in the solution set.
So, {12, -12} is the solution set.
