Multiply both sides by -8 to get k = -16
To check the solution, plug in -16 into the original equation. You do in-fact get 2
14000+7x=35x (x being the number of books) solve for x and you have your answer. 14000=35x-7x=28x therefore x=14000/28=500 so he needs to sell 500 books before he breaks even.
The answer would be 6x+3y=2
