Solve the following problem using substitution or elimination method.

Two rental car companies are running specials this month. At Johnson’s Rentals, customers will pay $50 to rent a mid-sized car for the first day, plus $2 for each additional day (x). At Martinez Rent-a-Car, the price for a mid-sized car is $30 for the first day and $4 for each additional day (x). How many additional days (x) would it cost the same to rent from either company? What is that cost?

Let x represent the number of additional days you will rent a car and y represent the total cost of renting the car. Write a system to represent the situation, and solve to answer the question.