John claims that he can get the same answer to the problem below by adding up (begin with 6+8) or by adding down (begin with 9+8). He wants to know why and if this works all the time. How do you respond?

Michael opens a store selling specialty artisan breads. before he can begin baking and selling bread, he purchases a bread oven. each week he sells the same number of loaves and earns the same amount of money. write an equation to show how much money he has earned at any week. x y week profit in dollars 1 –250 2 –170 3 –90 4 –10 5 70 a. y = 80x + 70 b. y = 80x – 330 c. y = 80x – 250 d. y = 80x