1. The problem statement, all variables and given/known data (50 - x - y)(x+y) - x - ((y^2)/2)) simplified: 50X - X^2 - XY - 50Y - XY - Y^2 - X - ((Y^2)/2) 2. Relevant equations 50X - X^2 - XY - 50Y - XY - Y^2 - X - ((Y^2)/2)) 3. The attempt at a solution for x: 49 - 2x - 2y for y: 50 - 2x - 3y The book has the same, except -1x and -1y (i.e. 49 - 1x - 2y) and (50 - 1x - 3y). Why is this?