4. Km wants to order pizza for her sister's birthday. She compares two pizza places to determine which
has the best deal for her. Papa Joanna's charges a rate
of $17 for each pizza with free delivery. Domenico's
charges a rate of $13.50 each pizza plus a delivery fee
of $21. The system of equations shown models the
total costs for buying x pizzas at each.
Papa Joanna's: y = 17x
Domenico's: y = 21 + 13.5x
How many pizzas would Kim need to order for the
total cost to be the same at both pizza places?