Question

Please help! Can’t get right

Answer 1

Check the picture below.

`\stackrel{h}{0}~~ = ~~-16t^2+32t+48\implies 0=-16(t^2-2t-3) \\\\\\ 0=t^2-2t-3\implies 0=(t-3)(t+1)\implies t= \begin{cases} 3 & \checkmark\\\\ -1 & \bigotimes \end{cases}`

notice, the -1 is a nogo, because when it hit the ground has to be a value greater than 0.