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anonymous

  • one year ago

I have a question, can anybody help me? What is the general form of the equation of the given circle with center A? http://cdn.ple.platoweb.com/PCAP-ASSETS-PROD/258cc385d685420384bc0a8b50aa8568 x2 + y2 + 6x − 24y − 25 = 0 x2 + y2 − 6x + 24y + 128 = 0 x2 + y2 + 6x – 24y + 128 = 0 x2 + y2 + 6x − 24y + 148 = 0

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  1. anonymous
    • one year ago
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    The equation of a circle with the center (h, k) and radius r is \[(x-h)^2+(y-k)^2=r^2\] Your center is (-3,12) so that's h and k. Your radius is 5. Plug in the numbers and expand the equation

  2. anonymous
    • one year ago
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    (x-(-3)2 + (y-12)2 = 25 right?

  3. anonymous
    • one year ago
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    yes

  4. anonymous
    • one year ago
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    and what do i do next ? :s

  5. anonymous
    • one year ago
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    foil (x+3)² and (y-12)²

  6. anonymous
    • one year ago
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    is it (x+9) + (y + 144) = 25 ??

  7. anonymous
    • one year ago
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    no. you need to use FOIL for both the x and y (x + 3)² + (y - 12)² = 25 means \[(x+3)(x+3)+(y-12)(y-12)=25\]

  8. anonymous
    • one year ago
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    so it would be 6x and 24y right?

  9. anonymous
    • one year ago
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    6x and -24y

  10. anonymous
    • one year ago
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    okay so we can take out b and c in the answers right?

  11. anonymous
    • one year ago
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    yes

  12. anonymous
    • one year ago
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    is it a?

  13. anonymous
    • one year ago
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    i don't know. I'm not actually working this problem. just following along to make sure your work is right. and now that I look it doesn't look like you can exclude both b and c yet

  14. anonymous
    • one year ago
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    Ugh, i suck at math x.x

  15. anonymous
    • one year ago
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    what did you get when you multiplied (x+3)(x+3)? you've got to show me something so I can see where you're going wrong

  16. anonymous
    • one year ago
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    6x and -24y

  17. anonymous
    • one year ago
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    you couldn't have gotten just 6x and -24y. Show me the whole equation

  18. anonymous
    • one year ago
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    once we got that part right I can show you how to simplify it into the form they want

  19. anonymous
    • one year ago
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    so this is what I got with FOIL (x-3) + (x-3) + (y-12) + (y-12) = 25

  20. anonymous
    • one year ago
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    not sure if you have to multiply the 25 too..

  21. anonymous
    • one year ago
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    ok. so FOIL is actually multiplication. it stands for First, Inner, Outer, Last. just to help you remember how to distribute. I'm going to show you (x - 3)(x - 3). |dw:1435246652683:dw|

  22. anonymous
    • one year ago
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    ok. so FOIL is actually multiplication. it stands for First, Inner, Outer, Last. just to help you remember how to distribute. I'm going to show you (x + 3)(x + 3). |dw:1435246844411:dw|

  23. anonymous
    • one year ago
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    all those - should be + because our equation was (x + 3)(x + 3)

  24. anonymous
    • one year ago
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    You try with (y -12)(|dw:1435246933731:dw|y-12)

  25. anonymous
    • one year ago
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    y2 - 24y + 144

  26. anonymous
    • one year ago
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    right. so the equation for the circle becomes \[x^2+6x+9+y^2-24y+144=25\]

  27. anonymous
    • one year ago
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    and you combine like terms right?

  28. anonymous
    • one year ago
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    yes. don't forget to subtract the 25 from the right side since they want that side to be 0.

  29. anonymous
    • one year ago
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    \[x ^{2} + y ^{2} -6x - 24y + 128 = 0\]

  30. anonymous
    • one year ago
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    close. +6x :)

  31. anonymous
    • one year ago
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    Yaaay!, omg you saved my life, thanks a lot n.n

  32. anonymous
    • one year ago
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    no problem

  33. anonymous
    • one year ago
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    can you help me out in another question? please ? :c

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