I have done two parts but no idea how to the third one.

The height, h, in meters, of a firecracker fired into the air can be modeled using the function h(t)=-5(x-4)^2+85, where t is the time, in seconds, after the firecracker is fired.
c) Use the graph to estimate
i) how long the firecracker is in the air
ii) the maximum height reached by the firecracker, and how long it takes to reach this maximum height

1 answer

the time in the air is t when h=0 again. So, just solve for h(t) = 0.

the max height is the vertex of the parabola, clearly when t=4.
Similar Questions
    1. answers icon 1 answer
    1. answers icon 1 answer
  1. Central Idea or Theme Quick Check5 of 55 of 5 Items Question Which of the following is the central idea of a story?(1 point)
    1. answers icon 1 answer
  2. Central Idea or Theme Quick Check1 of 5 1 of 5 Items Question Which of the following describes the theme of a story?(1 point)
    1. answers icon 7 answers
more similar questions