Plz, help fast! 30 point 3 question!!!

What is the solution to the system of the equations? x = y - 3 x + 3y = 13

Answer these questions showing your work plz

Dakota earned $7.50 in interest in account a and $18.75 in interest in account b after 15 months. if the simple interest rate is 4% for account a and 5% for account b, which account has the greater principal? explain. to make it a little easier, there is an image. good luck!