The distributive property is a source of many mistakes in algebra. When a negative sign, multiplication, or division is next to a set of parentheses, everything inside the parentheses will be affected.
The answer shown below is wrong. Try working your way through the problem backwards, from the answer up. As you find each mistake, try to identify the thinking behind it… what perspective led to the mistake? What should have been done instead?
Hint 1: the correct answer to the original problem is:
Hint 2: there are mistakes made between all pairs of lines except the last pair.