A common multiple is a number that is a multiple of two or more numbers. The common multiples of 3 and 4 are 0, 12, 24, .... The least common multiple (LCM) of two numbers is the smallest number (not zero) that is amultiple of both.
so to the given 9(x+2)(2x-1) and 3(x+2)
the LCM would be 9(x+2)(2x-1)