Probability Questions Help is needed plz

There were 816 people at a concert when a band started to play. after each song, only half the people stayed to hear the next song. how many people were left at the concert after x songs? write a function to represent this scenario.

Extra points! find the missing dimension! need asap

How many solutions does the nonlinear system of equations graphed below have? a. one b. zero c. four d. two