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
[tex]x=\frac{-b+/-\sqrt{b^2-4ac}}{2a}[/tex]
so for
0=-16t²+25t+3
a=-16
b=25
c=3
so
[tex]x=\frac{-25+/-\sqrt{25^2-4(-16)(3)}}{2(-16)}[/tex]
[tex]x=\frac{-25+/-\frac{625+192}}{-32}[/tex]
[tex]x=\frac{-25+/-\frac{817}}{-32}[/tex]
it has to be a positive time
so it will hit the ground after [tex]\frac{25+\sqrt{817}}{32}[/tex] seconds