Answer
it could be 73/x
Step-by-step explanation:
So if my ans was helpful u can follow me.
F(x)=-5t^2+20t+60
Divide everything by -5
f(x)=t^2-4t-12
(t-6)(t+2)
Set it up to zero
t-6=0. t+2=0
t=6. t=-2
Since you can’t have negative seconds, the answer is 6 seconds