## anonymous one year ago 3) How long does it take the apple to reach your friend? (**HINT: The time would be the x-coordinate of the highest point.) Double click on the space below to show your work. h(t) = – 16t2 + 38.4t + 0.96 H= Height. T= Time (seconds). I WILL FAN AND MEDAL FOR ANSWERS AND WORK.

1. anonymous

Set the equation = 0. Then use quadratic formula.

2. anonymous

It is supposed to be h(t) = -16t^2 + 38.4t + 0.96

3. anonymous

Ok! Set the equation = 0.

4. anonymous

$$\huge -16t^2+38.4t+0.96=0$$

5. anonymous

Do you know the quadratic formula?

6. anonymous

Then it would be $-38\pm \sqrt{38.4^{2}-4(-16)(0.96)} / 2(-16)$

7. anonymous

Right?

8. anonymous

@mathway

9. anonymous

The beginning is supposed to be -38.4 not just -38.

10. anonymous

Yes! Now solve for t. :) And since it is time, your answer shouldn't be the negative one.

11. anonymous

Let me know if you got an answer, so I may check if it's right. :)

12. anonymous

So then I get: $-38.4\pm \sqrt{1,536} / -32$ I'm confused on what to do after this step.

13. anonymous

$$\huge \frac{-38.4±\sqrt {1536}}{-32}$$ Frind the square root of 1536 first.

14. anonymous

$16\sqrt{6}$

15. anonymous

$$\huge \frac{-38.4±16\sqrt {6}}{-32}\rightarrow$$ $$\huge \frac{-38.4+16\sqrt {6}}{-32}$$ & $$\huge \frac{-38.4-16\sqrt {6}}{-32}$$

16. anonymous

Should it be in radical form or could it be in decimal form?

17. anonymous

So how do we get the answer from there? It should be in decimal form since we are trying to find how many seconds it takes the apple to reach your friend.

18. anonymous

Great! Now get a calculator and solve for it. Notice that $$\sqrt{6} =2.45$$.

19. anonymous

$$\huge \frac{-38.4+16(2.45)}{-32}$$ &$$\huge \frac{-38.4-16(2.45)}{-32}$$

20. anonymous

Still confusing?

21. anonymous

I got -0.02

22. anonymous

Or should it be positive 0.02? @mathway

23. anonymous

You're supposed to get $$\huge \color{red}{ \text{TWO}}$$ solutions. and $$-0.02$$ is one. And since it is negative, it can't be the time. So solve for the other one.

24. anonymous

2.4 seconds rounded.

25. anonymous

Correct! :)

26. anonymous

Thank you so much!!!

27. anonymous

No problem! :)