Answer:
12m2 - 2m + 6
Explanation:
First, you combine 4m2 and -8m2 because nothing is raised to a power higher than 2. 4m2 - -8m2 is the same as 4m2 + 8m2 which leaves you with 12m2 as your first term. Next, you combine m and 3m because these are each raised to a power of 1. m - 3m is the same as 1m - 3m which is -2m (your 2nd term). You are left with 6 and nothing to combine it with, so you simply add 6 to the end of you equation as the 3rd and final term.