## toxicsugar22 5 years ago 9y^2-8x^2+72y+16x+64=0 give the exact coordinates of any four points on the hyperbola

1. myininaya

let x=0 solve for y let y=0 solve for x you should get two solutions for each time so that is 4 solutions

2. toxicsugar22

can u help me put x for 0

3. myininaya

x=0 so we have 9y^2+72y+64=0 do you know how to solve this?

4. toxicsugar22

YES

5. toxicsugar22

6. myininaya

thats right you sound happy lol i think

7. toxicsugar22

yes

8. toxicsugar22

cant we foil

9. toxicsugar22

to make it smaller numbers

10. myininaya

i dont think there are any common factors but you see if the polynomial is factorable if you like

11. anonymous

hey myininaya can you help me out after with my trapezoidal rule question:)

12. toxicsugar22

so how do i do this

13. toxicsugar22

u do it and we will compare our answer

14. toxicsugar22

ok i got mine

15. toxicsugar22

16. toxicsugar22

did u get an anser

17. anonymous

this is weird i never recall ever learning hyperbola's in high school or college.

18. toxicsugar22

myininama are you still there

19. myininaya

sorry i was away

20. myininaya

$y=\frac{-72\pm \sqrt{72^2-4*9*64}}{2*9}$

21. toxicsugar22

ok

22. toxicsugar22

i got that

23. toxicsugar22

and then help me furthur

24. myininaya

with simplifying?

25. toxicsugar22

yes

26. toxicsugar22

27. myininaya

the bottom is 18 because 2*9=18 i would be 72^2-4*9*64 in my calculator if i were you

28. toxicsugar22

ok

29. anonymous

exact answer i get is $y=(-72\pm \sqrt{4968})\div18$

30. myininaya

y=(-72+ sqrt{329472})/18 y=(-72- sqrt{329472})/18

31. toxicsugar22

32. myininaya

lol hes right i accidently put + between the b^2 and the 4ac

33. myininaya

hey beehive if you want your fractions to look cooler you can use frac{5}{7} and this will give you 5/7 in the equation editor if you want

34. anonymous

ok thanks.

35. toxicsugar22

so myininaya how do u go from there

36. myininaya

what do you mean?

37. myininaya

you can find the other two points now if you want

38. anonymous

$y={-4} \pm \frac{\sqrt{4968}}{18}$

39. myininaya

we already let x be 0 now lets let y be 0 and we will stil get a quadratic like -8x^2+16x+64=0

40. myininaya

divide both sides by -8 so we have x^2-2x-8=0 (x-4)(x+2)=0 x=4 and x=-2 so our four coordinates are (4,0), (-2,0), (0,-4+sqrt(4968)/18),(0,-4-sqrt(4968)/18)

41. toxicsugar22

i dont think the last two points are correct

42. toxicsugar22

can we simply it

43. myininaya

what did you get when u did 72^2-4(9)(36) i dont have my calculator if it is 4968 then those are corret above

44. myininaya

i only have this calcutor on computer and i dont like to use it

45. toxicsugar22

i got 3888

46. toxicsugar22

inm i got 2880

47. myininaya

72^2=5184 4*9*64=2304 i mean 64 not 36

48. anonymous

myininaya where did you get 36. that's what i mean.

49. myininaya

2880

50. anonymous

2880 here also

51. myininaya

lol that should be under the square root sign not 4 thousand something number

52. toxicsugar22

ok thanks i got it

53. anonymous

squareroot of 4968 i think

54. myininaya

but 72^2-4(9)(36)=2880

55. myininaya

i mean 64 not 36