Numbers multiple of 9 and differents factor of 40

In the xy-plane, if the parabola with equation passes through the point (-1, -1), which of the following must be true?

Apool measures 12.3 feet by 16.6 feet. if the longer wall of the pool has a diagonal of 17.8 feet, what is the volume of the pool? (round to nearest tenth)

Your friend uses c=50p to find the total cost, c, for the people, p, entering a local amusement park is the cost of admission proportional to the amount of people entering the amusement park? explain.