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anonymous

  • one year ago

Factoring by groups this quadratic equations -9x^2+13x-4

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  1. anonymous
    • one year ago
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    check if this right: -9x^2+13x-4 -9x^2+9x+4x-4=0 9x(-x+1) +4(x-1)=0 what am I doing wrong? Why (-x+1) and (x-1) not equal?

  2. butterflydreamer
    • one year ago
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    you're close :) take a look here: |dw:1436245778372:dw|

  3. anonymous
    • one year ago
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    Thank you very much, you've been very helpful

  4. butterflydreamer
    • one year ago
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    you're welcome ^_^!

  5. nincompoop
    • one year ago
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    sometimes: \(-1 \times(-9x^2+13x-4) \) use AC-method \(9 \times 4 = 36 \) identify 2 factors of 36 (AC) that adds to \(|b| \), (13): yes 9 and 4 \(-1 \times (9x^2 - 9x - 4x +4) \) \( -1 \times[9x (x-1) -4(x-1)] \)

  6. nincompoop
    • one year ago
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    https://people.richland.edu/james/misc/acmeth.html

  7. anonymous
    • one year ago
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    Why did u multiply by -1?

  8. nincompoop
    • one year ago
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    to show you that there are different ways of making use of methods that you can come up with.

  9. nincompoop
    • one year ago
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    now let us take it up a notch and treat x-1 as one variable, say p \(-1 [9x(p) - 4(p)] \rightarrow -1(9xp - 4p) \rightarrow -p(9x-4)\) rewrite: and I will put it back into original by undoing the multiplication of -1 to make you at ease \(-p \rightarrow -1(x-1) = (-x+1)(9x-4) \) WELCOME to the world of MATH

  10. anonymous
    • one year ago
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    I have a another problem: −3x​^2+17x−20 −3x^​2​​+12x+5x−20 (−3x^​2​​+12x)+(5x−20) Is this correct so far.

  11. nincompoop
    • one year ago
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    let see what wolframalpha can tell us

  12. nincompoop
    • one year ago
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    try the AC method I showed you.

  13. nincompoop
    • one year ago
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    look at your coefficients A: B: C: \(3 \times 20 = 60 \) identify two factors of 60 that adds to \(|b| \) we have 12 and 5

  14. nincompoop
    • one year ago
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    this is a test of your arithmetic abilities mostly.

  15. anonymous
    • one year ago
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    (−3x^​2​​+12x)+(5x−20) -3x(x-4) +5(x−4) ok why GCF of (−3x^​2​​+12x) is -3x not 3x. Answer: (-3x + 5) ( x - 4)

  16. nincompoop
    • one year ago
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    because one is negative, guy

  17. nincompoop
    • one year ago
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    you can't escape the negative

  18. anonymous
    • one year ago
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    oh alright now I get it. Thanks for your help,sir. i appreciate it

  19. nincompoop
    • one year ago
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    do you get the AC-method yet? look at the wolfram alpha attachment I showed you and learn some techniques from it.

  20. anonymous
    • one year ago
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    Ac method is similar to factoring by grouping

  21. nincompoop
    • one year ago
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    perhaps... perhaps

  22. nincompoop
    • one year ago
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    depends on what it involves completing the square, AC-method and quadratic formula they all become handy depending on the problem in chemistry such as in related rates or reaction rates, we use quadratic formula sometimes.

  23. anonymous
    • one year ago
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    I think this is the easiest method: https://www.youtube.com/watch?v=r1JAJfmRG5w&list=LLJjHKJ71EvI51FoDSRsSy-g&index=5

  24. nincompoop
    • one year ago
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    it will depend on the problem you are given

  25. anonymous
    • one year ago
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    one last question: -9x^2+9x so the GCF of this binomial is -9x -9x(x-1)

  26. butterflydreamer
    • one year ago
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    that would be correct :)

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