Arock is thrown straight up into the air from a height of 4 feet. the height of the rock above the ground, in feet, t seconds after it is thrown is given by -16t^2+56t+4. for how many seconds will the height of the rock be at least 28 feet above the ground?

The revenue each season from tickets at the theme park is represented by t(c)=5x. the cost to pay the employees each season is represented by r(x)=(1.5)^x. examine the graph of the combined function for total profit and estimate the profit after four seasons