2x2 plus 15 equals 11x

2x2 + 15 = 11x ? Can be only for some values of x.

2x2 + 15 = 11x subtract 11x to both sides

2x2 - 11x + 15 = 0

(2x - 5)(x - 3) = 0

2x - 5 = 0 or x - 3 = 0

x = 5/2 or x = 3