Stevelyn went to Amelia's and bought x packages of spaghetti for $2 each and y jars of pasta sauce for $3 each and spent a total of $18. But upon returning home Stevelyn had pasta sauce already but was out of parmesan cheese. Stevelyn returned to Amelia's and bought x containers of parmesan cheese for $4 each and returned the pasta sauce bought on the first trip and still spent $18. The system of equations shown below represents the amounts, in dollars, Stevelyn spent on the two trips to Amelia's.
