How to expand and simplify expressions

Depending on the expression how to expand and simplify is different. Commonly for two brackets back to back these are expanded by the FOIL method. Multiply together the two first parts of the brackets, then the two outer, followed by the inner and then the last, be very careful with the signs. Then simplify by adding together any like parts of the equation. However one common mistake is not mirroring what is done on one side of the equation on to the other side. So if one side has 3x-7 and 7 is added to this side to simplify this side, 7 must be added to the other side of the equation. It can be easier if there is only a number or letter, followed by a bracket- but this mistake is still commonly made.