-3m - 6 = 18 -18 -6 = 3m -24 = 3m -24/3 = m -8 = m
So, First I moved the -3m to the other side so that it would be positive. Remember that when solving these equations, the purpose is to leave the letter by itself, so we leave 3m by itself by moving it to the other side and uniting the terms that are alike. 18 becomes -18 as I move it to the left side and -6 stays the same because it doesn't move.
You remember that when there are 2 negatives you add them because they have the same sign, and you leave the sign of the greatest number, so it stays "-".
Then, you simply divide -24/3 = m and you get that -8 = m.