You want to put the equation like $50 + $1.99x= $3.99x. Because its a one time fee of $50 and for every DVD (x) that cost $1.99 for the internet movie rental company. While the neighborhood rent is only $3.99 a DVD (x).
In order to find how much DVDs is needed so the cost can be the same is 25 DVDs. When you subtract the x variables so $3.99-$1.99= $2. Now your equation should look like this $50= $2x so then you divide $50 by $2 to get 25=x. If you plug 25 into the x variables you get $99.75=$99.75.
