The drama club is selling tickets to their play to raise money for the show's expenses. Each student ticket sells for $4 and each adult ticket sells for $7.50. The auditorium can hold a maximum of 140 people. The drama club must make a minimum of $750 from ticket sales to cover the show's costs. If xx represents the number of student tickets sold and yy represents the number of adult tickets sold, write and solve a system of inequalities graphically and determine one possible solution.