Find the lcm (least common multiple) of (5x-9) and (3x+ 8)

In order  to get the LCM of two binomial expressions (5x - 9) and (3x + 8), you need  to factor first each binomial if factorable.

In this given binomial expression (5x - 9) and (3x + 8), you do not need to factor both because they are not factorable.

Next thing to do is to multiply the two binomial expressions by using FOIL method.
     (5x - 9)(3x + 8) = 15x^2 + 40x - 27x - 72 = 15x^2 + 13x - 72

Therefore, the LCM of (5x - 9) and (3x + 8) is 15x^2 + 13x- 72.

The correct answer is 7