1) The starting height would be when x=0 as the ball has not been thrown yet so starting height is 3 ft.
The maximum height occurs at the vertex of this downward facing parabola. The x coordinate of the vertex is at -b/2a or -24/-32= 3/4. When x = 3/4 y = -16(3/4)^2 +24(3/4) +3= 12. ball reaches a maximum height of 12 feet after 3/4th of a second or .75 seconds
To find when the ball hits the ground solve 0= -16x^2 + 24 x +3 ( when the ball hits the ground height is zero )
multiply the equation by -1 to get 16x^2 -24x -3+ 0. Unfortunately this does not factor so you need the quadratic formula to solve x=24+sqroot[ (-24)^2 -4 x16 x-3)]32= (24+sqroot768 )/32= 1.616co ball hits the ground 1.616 seconds after it is hit. I omitted the - part of the quadratic formula since this would give us a negative time which does not make sense
2) You can use the same technique to answer part 2 Starting height is when x =0 which gives you a starting height of 4 feet. Find the x and y coordinates of the vertex. The y coordinate is the maximum height and the x coordinate is the time when this occurs. To find when the ball hits the ground set the equation to zero and solve. I will leave these for you to do