Q1: The perimeter of the triangle is a + b + c and if each side is the same then it's 3a. In this situation we may write it in its simplest form as 9m. Note that 3(3m) is also correct but it's not the simplest form.
Q2: You're correct, the distributive property of 3(3m) can be written as 3 (2m + m).
