Please help me plot this

With number 11 ( show how you got the answer)

The party planning committee has to determine the number of tables needed for an upcoming event. if a square table can fit 8 people and a round table can fit 6 people, the equation 150 = 8x + 6y represents the number of each type of table needed for 150 people.

y=2x−1 5x−4y=1 is (1,1)(1,1) a solution of the system?