9m + p + 12p + 4m + 3p

To simplify the expression, we can combine like terms:

9m + p + 12p + 4m + 3p

Combining the m terms, we have:

(9m + 4m) + p + 12p + 3p

Simplifying the m terms gives:

13m + p + 12p + 3p

Combining the p terms, we have:

13m + (1 + 12 + 3)p

Adding the p terms gives:

13m + 16p

Thus, the simplified expression is 13m + 16p.