LCM of 36 and 96 can be found by prime factorization method:
36 = 2 x 2 x 3 x 3
96 = 2 x 2 x 2 x 2 x 2 x 3
2 x 2 x 3 is common and the LCM is obtained by multiplying the common portion(2 x 2 x 3) with the remaining portion(2 x 2 x 2 x 3).
LCM = 2 x 2 x 3 x 2 x 2 x 2 x 3 = 288.
LCM of 36 and 96 is 288.
The first three common multiples of 36 and 96 are the first three multiples of 288.
So, the first three common multiples are 288, 576 and 864.