A high school robotics club sold cupcakes at a fundraising event. They charged $2.00 for a single cupcake, and $4.00 for a package of 3 cupcakes.
They sold a total of 350 cupcakes, and the total sales amount was $625.
The system of equations below can be solved for x, the number of single cupcakes sold, and y, the number of packages of 3 cupcakes sold.
{x+3y=3502x+4y=625

Multiply the first equation by 2. Then subtract the second equation. What is the resulting equation?