Question 1141219
after 3 seconds, t=3 and 2 would  be most efficient, although 1 is not bad.

the time it hits the ground is when -16t^2+64t=0, so when (t-4)=0 the equation is solved.
this is 16t^2-64t=0
16t(t-4)=0 or -16t(t-4)=0  and t=4 seconds so 3 is for B

estimate when football is 40 feet high would be when -16t^2+64t-40=0, and the first equation would be solved as a quadratic and be most efficient so 1 for C