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poopsiedoodle Group Title

Can someone help explain how to do quadratic equations with the quadratic formula? I'll give you a problem. See comments.

  • one year ago
  • one year ago

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  1. poopsiedoodle Group Title
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    \[\huge 0 = -4(-4t^2 -8t -1)\]

    • one year ago
  2. hba Group Title
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    Well the first step is to compare your equation with the standard form and get a,b and c \[\huge\ ax^2+bx+c=0\]

    • one year ago
  3. poopsiedoodle Group Title
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    So, how would I do that with this one? Multiply the parentheses stuff by -4?

    • one year ago
  4. hba Group Title
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    Seeing your question i would suggest you to first divide your whole equation by -4 and then compare

    • one year ago
  5. poopsiedoodle Group Title
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    \[\Huge 0=-4t^2 -8t-1\]

    • one year ago
  6. hba Group Title
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    What is a,b and c in this ?

    • one year ago
  7. poopsiedoodle Group Title
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    a=-4 b=-8 c=-1

    • one year ago
  8. hba Group Title
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    Good,Now you can use the quad formula. \[\huge\ x=\frac{ -b \pm \sqrt{b^2-4ac} }{ 2a }\]

    • one year ago
  9. hba Group Title
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    The other think which you can do with your equation is that you can take -1 common and then compare so everything becomes positive.you can also do it straight away :)

    • one year ago
  10. poopsiedoodle Group Title
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    so, t = -8*√64-4*-4 ------------------ 2*-4 ?

    • one year ago
  11. poopsiedoodle Group Title
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    which would then be t=-8*(8+4) ----------- -8

    • one year ago
  12. poopsiedoodle Group Title
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    am I getting it right?

    • one year ago
  13. hba Group Title
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    It should be +- not *

    • one year ago
  14. poopsiedoodle Group Title
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    I don't get it... wouldn't you be multiplying -8 and \[\pm √64-4*-4\]?

    • one year ago
  15. hba Group Title
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    t=-8(+-)(8+4) ----------- -8

    • one year ago
  16. poopsiedoodle Group Title
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    Now I'm rather confused.

    • one year ago
  17. hba Group Title
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    Lemme show you.

    • one year ago
  18. hba Group Title
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    I appreciate you working with me though.

    • one year ago
  19. poopsiedoodle Group Title
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    I guess I could do that \(\Huge\mathsf{:P}\)

    • one year ago
  20. hba Group Title
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    a=-4 b=-8 c=-1 \[\huge\ t=\frac{ -(-8) \pm \sqrt{(-8)^2-4(-4)(-1)} }{ 2(-4) }\]

    • one year ago
  21. poopsiedoodle Group Title
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    Ok, but what does the \[\pm\] do? what's its significance?

    • one year ago
  22. hba Group Title
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    Well when we simplify it we would be taking the adding part on one side and subracting part on the other side.

    • one year ago
  23. poopsiedoodle Group Title
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    so it'd be 8+√blahblahblah --------------- 2-(-4)?

    • one year ago
  24. hba Group Title
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    Either, 8+√blahblahblah --------------- 2-(-4)? Or, 8-√blahblahblah --------------- 2-(-4)?

    • one year ago
  25. poopsiedoodle Group Title
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    so the \[\pm\] just breaks up between the denominator and the numerator?

    • one year ago
  26. hba Group Title
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    Exactly.

    • one year ago
  27. poopsiedoodle Group Title
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    Ah. I guess I'll try another problem here and ask you if it's right or something.

    • one year ago
  28. hba Group Title
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    Sure :)

    • one year ago
  29. poopsiedoodle Group Title
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    \[\huge 0=-2x ^{2} +14x +20\] \[\large x=\frac{ -14\pm \sqrt{14^2 - 4(-2+20)} }{ -4 }\] \[\large x= \frac{ -14+14-72 }{ -4 }\]

    • one year ago
  30. poopsiedoodle Group Title
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    and the answer is \[\huge \frac{ -7\pm \sqrt{89} }{ 2 }\]. Would I be right?

    • one year ago
  31. hba Group Title
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    Its is -4(a)(c) not -4(a+c)

    • one year ago
  32. poopsiedoodle Group Title
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    oh. Well that ruins that then.

    • one year ago
  33. hba Group Title
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    Yes it does :) Do it on a paper and tell me what you got from that equation :)

    • one year ago
  34. poopsiedoodle Group Title
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    \[\Large x=\frac{ -14\pm \sqrt{14^2 - 4(-2*20)} }{ -4 }\] \[\Large x=\frac{ -14\pm 14 - 4(-40)} { -4 }\] \[\Large x=\frac{ -14\pm 14-160} { -4}\] \[\Large x=\frac{ -14\pm -146} {-4}\] set x to 0 and divide all by -2 to get \[\Large \frac{ 7\pm 73} { 2}\]

    • one year ago
  35. poopsiedoodle Group Title
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    and now I'm confused.

    • one year ago
  36. poopsiedoodle Group Title
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    oh wait, I forgot to keep the x's in there. Crap.

    • one year ago
  37. poopsiedoodle Group Title
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    Think you could help me out here? My mind is about to implode.

    • one year ago
  38. hba Group Title
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    x=7+73/2,x=7-73/2

    • one year ago
  39. hba Group Title
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    Btw, (-) *(-)=+

    • one year ago
  40. hba Group Title
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    So just because of signs it goes wrong.

    • one year ago
  41. hba Group Title
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    \[\Large x=\frac{ -14\pm 14 - 4(-40)} { -4 }\] Continue from here.

    • one year ago
  42. poopsiedoodle Group Title
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    But I left the xs out of my work. ._.

    • one year ago
  43. hba Group Title
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    No worries about that :)

    • one year ago
  44. hba Group Title
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    Continue working from here.

    • one year ago
  45. poopsiedoodle Group Title
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    \[\Large x=\frac{ -14\pm 14 - 4(-40)} { -4 }\] \[\Large x=\frac{ -14\pm 14+160} {-4}\] \[\Large x=\frac{ -14\pm 174} {-4}\] \[\Large x=\frac {\frac{ -14\pm 174} {-4}} {-2}\] \[\Large x=\frac {7\pm -87} {2}\]

    • one year ago
  46. poopsiedoodle Group Title
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    And now what do I do?

    • one year ago
  47. hba Group Title
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    I don't know what you are upto ,where did that divide by -2 come in between ?

    • one year ago
  48. poopsiedoodle Group Title
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    Well, I'm not sure. I just thought I had to do that. I'm rather confused ._.

    • one year ago
  49. hba Group Title
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    Hmm,If OS would be working on chrome i would have worked one problem for you. Can we do this later ?

    • one year ago
  50. poopsiedoodle Group Title
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    I'm using chrome right now o_o But, I guess that'd be OK :P

    • one year ago
  51. hba Group Title
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    Thanks.

    • one year ago
  52. poopsiedoodle Group Title
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    Thanks to you too :3

    • one year ago
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