The following equation is solved incorrectly. Identify the mistake and then correctly solve the equation:
y - 1 = - 3
Incorrect solution:

Answer
The mistake: 1 was added to the left-hand side, while 1 was subtracted from the right-hand side. The correct answer: add 1 to each side to get y = - 2. Never forget that you must treat both sides equally. They're like kids: you just can't show favoritism...even if one of them is cuter.