Answer:
23
Explanation:
-3x + m = 2x + 8
-5x + m = 8
to figure this out at this point you have to think about what -5 times 3 would equal which would be -15, then think about what number m would have to be in order to get -15 when adding/subtracting m from 8.
-5x + 23 = 8
-5x = -15
-15 / -5 = 3