6x(6x) + 11x - 35 = 0
36x^2 + 11x - 35 = 0
36x^2 + 11x = 35
 
-11 + or - square root 11^2 - 4 (36) (-35)
 divided by 
 2 * 36 
-11 + or - square root 5161
 divided by
 72
-11 + or - 71.84
 divided by
 72
There are two answers to the problem:
-11 + 71.84 / 72 = -10 rounded
-11 - 71.84 / 72 = -12. rounded
welcome :/