1. Suppose you get a job selling T-shirts at a concert. You get $2 for each T-shirt you sell, but it costs you $5 to get into the concert. How many T-shirts will you have to sell in order to come home with $25?

Let x = the number of T-shirts you sell. If you get $2 for each T-shirt you will make $2x, but if you have to pay $5 to get into the concert, the amount of money you make will be given by the formula 2x - 5. If the amount of money you need to bring home is $25, we get the equation

Add 5 to both sides

Divide both sides by 2

or