Allen is reviewing his receipts from three different visits to a spa, trying to determine the individual costs of his
favorite spa treatments. From his receipts he knows:
A manicure and a back rub together
cost $18.
A back rub and a facial together
cost $19.
A manicure and a facial together
cost $21

Lian is deciding which of two gyms to join. each gym charges a monthly rate plus a one-time membership fee. lian correctly wrote and solved a system of linear equations by substitution to compare the costs of the memberships. in her work, she substituted an expression for one variable and solved for the other. this resulted in the equation 75 = 75. what can lian conclude? one gym charges $75 per month. each gym charges $75 per month both gyms charge the same monthly rate and the same membership fee. both gyms charge the same monthly rate, but not the same membership fee.