Answer:
he's not correct.
-15 = m
Explanation:
-16 = -1 + m
-16 + 1 = m
-15 = m
Why does -1 became +1 , It is because you are adding 1 on both side so that we can cancel out the -1 and it will rest the m.
like this;
+1 -16 = -1 + m +1
-16 + 1 = (0 or nothing) + m
-15 = m