Answer :

If m= -3, you would substitute -3 as m. So, 5(-3). Your answer would be -15!
loreal33
When they give you the value for the variable, all you gotta do is to substitute it (Where you replace the variable/letter with the number it equals to).

So in this case, m = -3.

5m = 5(-3) = -15


Hope it helped :)