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kevin8374 Group Title

solve for r r^2+3r=8 Example r^2+3r=1 r=-3+√13/2,-3-√13/2

  • 2 years ago
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  1. philips13 Group Title
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    looks like the quadratic equation might help here

    • 2 years ago
  2. brinethery Group Title
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    r^2 +3r -8 =0 a=1 b=3 c=-8 Use the quadratic formula to get your answer(s) for x.

    • 2 years ago
  3. kevin8374 Group Title
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    The quadratic equation is where my problem lies

    • 2 years ago
  4. brinethery Group Title
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    Do you know what the quadratic formula is?

    • 2 years ago
  5. brinethery Group Title
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    http://0.tqn.com/d/create/1/0/i/9/9/-/Quadratic.formula.jpg

    • 2 years ago
  6. brinethery Group Title
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    ((-1) +/- sqrt ((3)^2-(4)(1)(-8)))/((2)(1))

    • 2 years ago
  7. brinethery Group Title
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    (-1 +/- sqrt (41))/2 ***THAT MEANS*** x = (-1 + sqrt(41))/2 x = (-1 - sqrt(41))/2

    • 2 years ago
  8. kevin8374 Group Title
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    Thanks so much

    • 2 years ago
  9. brinethery Group Title
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    This is what you do whenever factoring is impossible.

    • 2 years ago
  10. brinethery Group Title
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    Or if you're too lazy to factor :-)... like I usually am LOL

    • 2 years ago
  11. kevin8374 Group Title
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    so how would i put x^2+7x=10 into the quadratic equation

    • 2 years ago
  12. brinethery Group Title
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    Okay so your format is going to be ax^2+bx+c So with x^2+7x=10, you always always always get everything on the left side. You're setting it equal to zero. x^2+7x-10=0 Now what are a, b, and c?

    • 2 years ago
  13. kevin8374 Group Title
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    sorry typed problem wrong x^2+7x-10=0

    • 2 years ago
  14. brinethery Group Title
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    k... so what do you think a, b, and c are?

    • 2 years ago
  15. kevin8374 Group Title
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    a is 1 b is 7 c is 10

    • 2 years ago
  16. brinethery Group Title
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    Yup!

    • 2 years ago
  17. brinethery Group Title
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    I'll ask you one now. -x^2+2x+3 What is "a" in this case?

    • 2 years ago
  18. kevin8374 Group Title
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    -1

    • 2 years ago
  19. brinethery Group Title
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    yep

    • 2 years ago
  20. kevin8374 Group Title
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    my problem is keeping it all in order

    • 2 years ago
  21. brinethery Group Title
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    Now if there's a term, say b=-2 and you need to plug it into your formula, the first thing you're putting in is -b. So how to do that: -(-2). So that will be a +2.

    • 2 years ago
  22. brinethery Group Title
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    I understand. And I would recommend to do the problem in as many steps as you need to. And to slow down and pay close attention. I took an engineering problems course last quarter and I made a lot of mistakes when I didn't pay attention :-)

    • 2 years ago
  23. brinethery Group Title
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    You can try that problem and we'll compare answers if you want.

    • 2 years ago
  24. kevin8374 Group Title
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    ok is it -7+√89/2,-7-√89/2

    • 2 years ago
  25. brinethery Group Title
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    That's what I got too. You know what you're doing!

    • 2 years ago
  26. kevin8374 Group Title
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    You have no idea how much you have helped me thanks again!!!!!

    • 2 years ago
  27. brinethery Group Title
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    I'm glad :-) So step 1: Get everything on the left side so that it's set equal to zero. step 2: write down what your a, b, and c values are step 3: plug in to the formula and go slow

    • 2 years ago
  28. kevin8374 Group Title
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    I truly cannot thank you enough I have been struggling for days

    • 2 years ago
  29. brinethery Group Title
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    I would recommend Paul's online notes as an alternative to your book. Most algebra books truly suck. http://tutorial.math.lamar.edu/Classes/Alg/SolveQuadraticEqnsII.aspx

    • 2 years ago
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