A rock is thrown in the air from the edge of a seaside cliff. Its height in feet is represented by f(x) = –16(x2 – 8x-9), where x is the number of seconds since the rock was thrown. The height of the rock is 0 feet when it hits the water. How long does it take the rock to hit the water? How many seconds?

where's the diagram?

step-by-step explanation:

i am not sure :

step-by-step explanation:

step by step solution :

step   1   :

1.1     4 = 22

(4)3 = (22)3 = 26

equation at the end of step   1   :

  ((23) • 26)2

step   2   :

equation at the end of step   2   :

  (23 • 26)2

step   3   :

final result :

  218

ya