Respuesta :
Hello,
f(x)=0
-10x(x-4)=0
x=0 or x=4
Launch : time 0
Landing,:time 4
Duration=4-0=4 (s)
f(x)=0
-10x(x-4)=0
x=0 or x=4
Launch : time 0
Landing,:time 4
Duration=4-0=4 (s)

4 seconds is how long, 100% correct just got it right on the quiz.