Help round to nearest object please

The parabola opens: y=√x-4 (principal square root) up down right left

Write an algebraic expression for the word expression the quotient of c and 8

Michael gose to a theme park and rides two different roller coasters that both begin on a raised platform his height while on the first roller coaster measured in feet from the platform height can be modeled by the following graph where t is the number of seconds since the ride began