Please help me with these questions!!

truck is 100mph

Step-by-step explanation:

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