Answer:
After 11 seconds the hovercraft will land on ground
Step-by-step explanation:
Given function that shows the height of a hovercraft,
[tex]h(x) = -(x-11)(x+3)[/tex]
Where,
x = number of second.
When the hovercraft land the ground,
[tex]h(x) = 0[/tex]
[tex]-(x-11)(x+3)=0[/tex]
[tex]\implies (x-11)(x+3)=0[/tex]
By zero product property,
x - 11 = 0 or x + 3 = 0
⇒ x = 11 or x = -3 ( not possible ),
Hence, after 11 seconds the hovercraft will land on ground.
at the time I am writing this the other answer only has a 3.2 rating, but I can vouch that the answer is still correct: 11 seconds !