In order to get the LCM of a two binomial expression, first thing you have to do is to factor each binomial expression if factorable. In the given binomial expression (5x - 9) and (3x + 8), you do not need to factor both since they are not factorable. The next thing you do is to multiply the two binomial expression by using FOIL method. (5x - 9)(3x + 8) = (15x^2 +40x - 27x - 72) = 15x^2 + 13x - 72. Therefore, 15x^2 + 13x - 72. is now your LCM.
