TIMED QUESTION! Audrey throws a ball in the air, and the path the ball makes is modeled by the parabola
y = −0.018(x − 20)

2 + 8 , measured in feet.
a. What is the maximum height the ball reaches,

b. How far (horizontally) from Audrey does is the ball at its maximum height?

c. How far does the ball travel before it hits the ground?

d. How high is the ball after 3 seconds?

Since the quadratic is basically already in vertex form (y=a(x−h)2+k, where (h,k) is the vertex), we can see that the vertex from 0=−0.018(x−20)2+8 is (20,8).

This means that the maximum height (since the parabola opens downward) is 8 feet and it happens 20 feet away from Audrey

When the ball hits the ground, y=0, so we have 0=−0.018(x−20)2+8. We could expand the binomial and use the quadratic formula, but it’s much easier to use the square root method, since we have a square in the original:

0−8−0.018±80.018−−−−−√x−20x=−0.018(x−20)2+8=(x−20)²=(x−20)²−−−−−−−−√=±21.08=41.08

Note that we had to “throw away” the negative part of the solution. The ball will hit the ground 41.08 feet from Audrey.

Really I can't understand it because of ² and 2

answer: 1inch=7days  

12inch=12*7=84days

step-by-step explanation: