The height

y

(in feet) of a ball thrown by a child is

y

=

−

1/14

x2

+

6x

+

3

where

x

is the horizontal distance in feet from the point at which the ball is thrown.

(a) How high is the ball when it leaves the child's hand?

3

Correct feet

(b) What is the maximum height of the ball?

129

Correct feet

(c) How far from the child does the ball strike the ground? ___ feet

I just need c answered , the rest. is correct

The ball describes a parabola, as you can see in the attached picture. So, the point where the ball strike the ground is the point where the parabola meets the x axis. In fact, the x-axis is the set of points where y=0, which means that the ball has height 0 or -again- it hits the ground.

So, we have to set y=0 in our equation and look for the positive solution. We have

And the positive solution is

So that's the distance from the child where the ball strikes the ground.

#1. 50 tens or 5 hundreds

#2. 110 tens, 11 hundreds, or 1 thousand 1 hundred

#3. 300 tens, 30 hundreds, or 3 thousands.

#4. 2500 tens, 250 hundreds, 25 thousands, or 2 ten thousands 2 thousands

#5. 6000 tens, 600 hundreds, 60 thousand, or 6 ten thousands.

#6. 11000 tens, 1100 hundreds, 110 thousands, or 11 ten thousands.

#7. 2500 tens, 250 hundreds, 25 thousands, or 2 ten thousands 5 thousands

#8.90000 tens, 9000 hundreds, 900 thousands, or 90 ten thousands