Question

A toy rocket was launched from the ground. The function f(x) = -16x2 + 160x shows the height of the rocket f(x), in feet, from the ground at time x seconds.
What is the axis of symmetry of the graph of f(x), and what does it represent?

Answer 1

x = 10; it takes 10 seconds to reach the maximum height and 10 seconds to fall back to the ground
x = 10; it takes 10 seconds to reach the maximum height and 20 seconds to fall back to the ground
x = 5; it takes 5 seconds to reach the maximum height and 10 seconds to fall back to the ground
x = 5; it takes 5 seconds to reach the maximum height and 5 seconds to fall back to the ground

Answer 2

the axis of symmetry is used in the general quadratic formula and is

\[t = \frac{-b}{2 \times a}\]

in your question a = -16 and b = 160

just substitute the values to axis of symmetry

Answer 3

the axis is symmetry is where the rocket reaches it's maximum height.

Answer 4

okay so then you would want to put in either 5 or 10 into the equation?

Answer 5

the vertex is where the rocket reaches its maximum height... so substitute the value from the axis of symmetry to get the max height