One way of solving systems of linear equations is by adding a multiple of one equatio

There are two factors that limit how much he can bake in a week: He only wants to work for 40 http://session.masteringphysics.com/...%5Crm+hours%7D a week and he only has one oven. Suppose that it takes the baker 1http://session.masteringphysics.com/...%5Crm++hour%7D to prepare a pair of cakes or a gross of cookies (before they are placed in the oven). Since he only wants to work 40 http://session.masteringphysics.com/...%5Crm+hours%7D a week, his output of pairs of cakes http://session.masteringphysics.com/render?var=x and his output of grosses of cookies http://session.masteringphysics.com/render?var=y are constrained by the equation http://session.masteringphysics.com/...tex=x%2By%3D40.

To maximize the profit of the bakery, the first step is to find where the equations for all of the constraints intersect. For the following part, you will look at http://session.masteringphysics.com/...tex=x%2By%3D40 and http://session.masteringphysics.com/render?tex=y%3D0, which is also a constraint (specifically a minimum) since the baker cannot make a negative number of cookies.

What should you multiply the equation http://session.masteringphysics.com/render?tex=y%3D0 by so that when added to http://session.masteringphysics.com/...tex=x%2By%3D40 the variable http://session.masteringphysics.com/render?var=y will cancel out?