Does anyone know how to solve this?

Answer: m = -1
Step-by-step explanation:
-13 - 5m = -4 + 4m
First you want to get the m's on the same side, and remember, what you do to one side you do to the other.
-13 -5m + 5m = -4 + 4m +5m
-13 = -4 + 9m
Now, isolate the m
-13 + 4 = -4 + 9m + 4
-9 = 9m
-9/9 = 9m/9
-1 = m
Check
-13 - 5(-1) = -4 + 4(-1)
-13 + 5 = -4 - 4
-8 = -8
Hope this explains it!