Easy way to do this is draw the point on graph paper and count the same units above/below the x-axis. This example you are 7 units above the x-axis so you would count 7 units below the x-axis giving you the point.
To write the function correctly, it is important to assign variables correctly and understand the situation of the problem clearly. For this, we let y the number of people and x as the number of songs played.
At x = 0 y = 567 at x = 1 y = 567 - 567(1/3) at x = 2 y = 567 - 567(1/3)(1/3) at x = 3 y = 567 - 567(1/3)(1/3)(1/3)
Therefore, the number of people left after x songs would be represented by the equation:
