## anonymous one year ago A Daredevil Jumps Off A Tall Building. He Falls Freely For Several Seconds Before Releasing His Parachute . His Height (h) In Meters , T Seconds After Jumping Can Be Modeled By : h=-4.9t^2+t+360 before he releases his parachute and h=-4t+142 After He Releases His Parachute . How Long After Jumping Did He Release His Parachute ? HELPP ME PLEASE !!!! @imqwerty

1. anonymous

The height functions will be equal when he releases the parachute \[-4.9t^2+t+360=-4t+142\] Make one side equal to 0 and use the quadratic equation to solve

2. Plasmataco

He falls for218 meter

3. anonymous

How ?

4. Plasmataco

5. anonymous

im asking whoever can help me solve thus problem

6. anonymous

Do you know the quadratic equation?

7. anonymous

No But I Know How To Do The Formula

8. anonymous

sry, I meant formula

9. anonymous

The equation is in my first post

10. anonymous

11. anonymous

what do you have?

12. anonymous

-4.9t^2 + t +360 = 4t +142

13. anonymous

Thats All I Have I Dont Know The Next Step.

14. anonymous

It should be -4t + 142 on the right side. the next step is to make one side be 0 by adding or subtracting everything on that side of the equation. You have -4t on the right side. How would you move it from the right to the left?

15. anonymous

16. anonymous

By Drawing So I Can Get A Visual Picture .

17. anonymous

Is one of these what you want? Not really sure what you're asking for?|dw:1439936124822:dw| |dw:1439936251767:dw|

18. anonymous

So Where It Says Add Or Subtract ?

19. anonymous

ill subtract the 4t

20. anonymous

You want to add the 4t because it's actually -4t (at least it is in the original problem statement). Whatever the sign is, do the opposite

21. anonymous

Ok Can You Draw It Out ?

22. anonymous

|dw:1439936950147:dw|

23. anonymous

Right Right There It Is

24. anonymous

AND Now I Do The Formula .

25. anonymous

Correct ?

26. anonymous

yeah, what did you get as the equation though? I left the addition/subtraction for you to do

27. anonymous

-4.9t^2 + 364 -142=0

28. anonymous

I aligned the terms so you can actually add straight down. What's\[t+4t=\] and \[360-142=\]

29. anonymous

4t^2 and 218

30. anonymous

t + 4t = 5t (add the coefficients, never change the exponents when adding or subtracting). So this is the equation |dw:1439937754826:dw|

31. anonymous

I Plugged Them In.

32. anonymous

ok. what did you get for t?

33. anonymous

x=-6 x2=7

34. anonymous

yeah, closer to -6.2 and 7.2?

35. anonymous

Yeah

36. anonymous

Do You Mind Helping Me Again Ill Tag You If So

37. anonymous

yeah

38. anonymous

Ok