Question

Tiffany kicks a soccer ball off the ground and in the air, with an initial velocity of 28 feet per second. Using the formula H(t) = -16t2 + vt + s, what is the maximum height the soccer ball reaches?

15.6 feet
14.1 feet
13.5 feet
12.3 feet

Answer 1

\(\sf H(t) = -16t^2 + vt + s\)

Okay, plu gin what we know:

\(\sf H(t) = -16t^2 + 28t + 0\)

Now find the vertex, which will be the maximum height.

Answer 2

Yet again IGreen beats me to the answer :P

Answer 3

Formula to find the x-value:

\(\sf \dfrac{-b}{2a}\)

Answer 4

Our equation is in the form of:

\(\sf ax^2 + bx + c\)

So in this case:

\(\sf a = -16\)
\(\sf b = 28\)

Answer 5

@GhostVortex :P

Answer 6

yea um so do you add 16 to the other side and then subtract the 28

Answer 7

So we have:

\(\sf \dfrac{-b}{2a}\)

\(\sf \dfrac{-28}{2(-16)}\)

Simplify

Answer 8

so you dont

Answer 9

No..just multiply 2 * -16 and divide.

Answer 10

Then we plug it back into the equation to find the maximum height.

Answer 11

Tell me what you get.

Answer 12

yup

Answer 13

28/-32

Answer 14

7/8

Answer 15

but i dont think you cn really divide that

Answer 16

Yes, you can..

7 / 8 = 0.875

Answer 17

Just plug it in your calculator..anyway that's 't', so we plug it back into our equation.

Answer 18

\(\sf H(t) = -16t^2 + 28t\)

\(\sf H(t) = -16(0.875)^2 + 28(0.875)\)

Can you simplify that?

Answer 19

yes its 12.25

Answer 20

Yep! That's our answer.

Answer 21

k thx

Answer 22

@iGreen can u help me with another one

Answer 23

I might be able to.

Answer 24

What are the approximate solutions of 4x2 + 2x = 17, rounded to the nearest hundredth?

x ≈ -2.33 and x ≈ 1.83
x ≈ -1.83 and x ≈ 2.33
x ≈ -9.31 and x ≈ 7.31
No real solutions

Answer 25

@kate_liller

Answer 26

4x² + 2x - 17 = 0
x = -2/8 ± √(4 + 16•17) / 8
x = -1/4 ± √(1 + 4•17) / 4
x = -0.25 ± 2.0767
x ≈ 1.83 or x ≈ -2.33 which is the 1st choice

Answer 27

thxs so much kate

Answer 28

@haydentroy can u give her a medal for me