[tex]y=-16t^2\text{ + 400}[/tex]
Simplifying the above function
[tex]y=-16(t^2-25\text{)}[/tex]
The axis of symmetry will be obtained when y = 0
[tex]\begin{gathered} 0=-16(t^2-25\text{)} \\ \text{Dividing both sides by -16} \\ t^2\text{ - 25 = 0} \end{gathered}[/tex][tex]\begin{gathered} t^2\text{ = 25} \\ t\text{ =}\sqrt[\square]{25} \\ \\ t\text{ =5} \end{gathered}[/tex]
