When the height is 0 that is when it hits the ground
solve
0=-16t²+25x+3
cant factor so use quadratic formula
for
0=ax²+bx+c

so for
0=-16t²+25t+3
a=-16
b=25
c=3
so



it has to be a positive time
so it will hit the ground after

seconds
The unit numbers can be 2,4,6.Suppose 2 as the unit number we can form 20 numbers the same way for 4 and 6 so totally 60 numbers.
Rewrite the parabola in standard form and use this formula to find the vertex (h,k).
= (2,-1)