36x^2-121=0

36x^2-121=0   factor as a difference of squares

(6x + 11) (6x - 11)  = 0

Set each factor to 0

6x + 11  = 0                                           6x - 11  = 0

Subtract 11 from both sides                  Add 11 to both sides

6x  = -11                                                 6x  = 11

                     Divide both sides by 6

x =  -11/6                or                        x =  11/6