posted by matthew .
what is m+4=1
You have to get the variable (or the letter) by itself. In order to get rid of the +4 on the same side as the m, you need to perform the opposite operation. When you -4 from that side, the 4 goes away and leaves the m by itself. What you do to one side, you have to do to the other to keep it balanced. So 1-4 is -3. Therefore, m = -3
Put -3 in the place of m to check and make sure you are right.