The instructions for this problem are: Given the ordered pair (1.3) write an equation for the line and graph it. I came up with this: x +y= 4. The answer at the back of the book is: x= y-2. Why is the one correct and the other not? They can't both be right because they graph two different slopes.

There is something very elementary here that I am missing. I almost know what it is but can't quite express it.