45 = -10 - y

Here is how I tried to solve the problem. Judging from the section of the book I'm working in, there should have been some multiplication involved.

45 + 10 = -10 - y + 10(Add 10 to both sides.)

55 = y

By checking the original equation, I came up with a false statement.

45 = -10 - 55

45 = -65

Any hints?