A football is kicked straight up into the air. Its height above the ground is approximated by the relation y=25x-5x^2 , where y is the height of the ball in meters and x is the time in seconds. There are two times when the football is 27.5 m in the air, on the way up and on the way down. Joe realizes that using the equation y = 27.5, he can determine the two times the ball is 27.5 meters in the air. Algebraically or graphically determine these two times.