1. Put numbers that are on the same group. 3x = 18-15 (3 has x so it is separated from whole numbers 15 and 18) (15 became negative because you moved it to the other side of the equals sign)
2. Simplify 3x = 18-15 3x = 3
3. Find x Transfer 3 on 3x to the right side denominator (bottom) That will make: x = 3/3