To simplify this expression, we can follow the order of operations (PEMDAS):

First, simplify the expression in the numerator:
M - 3/2M - M(2) - 16/M
= M - 3M/2 - 2M - 16/M
= M(1 - 3/2 - 2) - 16/M
= M(-1/2) - 16/M
= -1/2M - 16/M

Next, simplify the expression in the denominator:
1/3M + 12
= 12 + 1/3M
= 1/3M + 12

Now, putting the numerator and denominator together, we get:
(-1/2M - 16/M) / (1/3M + 12)

Therefore, the simplified expression is (-1/2M - 16/M) / (1/3M + 12).