Please help me find the answer

Danielle earns a 7.25% commission on everything she sells at the electronics store where she works. she also earns a base salary of $750 per week. what were her sales last week if her total earnings for the week were $1,076.25?

How long must $542 be invested at a rate of 7% to earn $303.52 in interest? in a easier way

What is the solution to the system of equations? y=1.5-3 y=-x