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denise9423 Group Title

Can someone plz help me get started on these fractions f(x)=3x-8 div 4x+20

  • 2 years ago
  • 2 years ago

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  1. AsianDuck Group Title
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    What do you need?

    • 2 years ago
  2. saifoo.khan Group Title
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    \[\frac{ 3x - 8}{4x + 20}\to \frac{3x-8}{4(x+5)}\]As there is nothing common between denominator and numerator so we cannot simply it.

    • 2 years ago
  3. denise9423 Group Title
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    sorry I just found this.

    • 2 years ago
  4. saifoo.khan Group Title
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    No worries! :D

    • 2 years ago
  5. denise9423 Group Title
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    How do I find the domain

    • 2 years ago
  6. denise9423 Group Title
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    hi

    • 2 years ago
  7. Akshay_Budhkar Group Title
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    domain is all real numbers except for -5

    • 2 years ago
  8. brinethery Group Title
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    No division by zero. So what is x going to be when the denominator is zero?

    • 2 years ago
  9. denise9423 Group Title
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    0

    • 2 years ago
  10. saifoo.khan Group Title
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    set the denominator equal to zero right? @Akshay_Budhkar

    • 2 years ago
  11. brinethery Group Title
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    no. x cannot = -5.

    • 2 years ago
  12. Akshay_Budhkar Group Title
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    Yes @sai

    • 2 years ago
  13. Akshay_Budhkar Group Title
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    @saifoo.khan

    • 2 years ago
  14. denise9423 Group Title
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    f(x)=3x-8 over 4x+20

    • 2 years ago
  15. brinethery Group Title
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    @denise9423 Domain means all of the values x can take on. Here's your domain: \[x \neq-5\]

    • 2 years ago
  16. Akshay_Budhkar Group Title
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    If you have a look the function is having real values for all values except for x=5 when it is not defined as the denominator is zero

    • 2 years ago
  17. denise9423 Group Title
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    can you show me how to get 5

    • 2 years ago
  18. brinethery Group Title
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    4x+20 =0 Solve for x. x=-5.

    • 2 years ago
  19. brinethery Group Title
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    Do you know why division by zero is not allowed?

    • 2 years ago
  20. denise9423 Group Title
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    ok,then can i sub it also 3x-8

    • 2 years ago
  21. brinethery Group Title
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    no!

    • 2 years ago
  22. brinethery Group Title
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    you only need to worry about the bottom.

    • 2 years ago
  23. denise9423 Group Title
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    no to ur question ok

    • 2 years ago
  24. brinethery Group Title
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    Remember this: What is 1 divided by 0? In other words, what times zero can equal 1? 0*2? 0*3? There is nothing you can multiply by zero to get 1. So whenever you get these fractions and they ask you to find the domain, just think about what x has to be in order for the denominator to equal zero.

    • 2 years ago
  25. brinethery Group Title
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    If you have an equation in the denominator, then set that equal to zero :-)

    • 2 years ago
  26. brinethery Group Title
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    *and solve for x.

    • 2 years ago
  27. denise9423 Group Title
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    like this 4x+20=0

    • 2 years ago
  28. brinethery Group Title
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    Yup! :-)

    • 2 years ago
  29. denise9423 Group Title
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    ok

    • 2 years ago
  30. brinethery Group Title
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    Or if you have 1/(x^2+2x+3) . If you have something weird like that, then set it equal to zero and use the quadratic formula to solve for your two x-values. Those x-values are what x can't equal. Sorry, I sound like I'm talking in riddles lol.

    • 2 years ago
  31. denise9423 Group Title
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    ok so -7xyy over 28xxxxxy=0

    • 2 years ago
  32. brinethery Group Title
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    Are you in algebra?

    • 2 years ago
  33. denise9423 Group Title
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    yes and Its rough

    • 2 years ago
  34. brinethery Group Title
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    I'm gonna be more specific with what I said, sorry my fault: Or if you have 1/(x^2+2x+3) . If you have something weird like that, then set it equal to zero and use the quadratic formula to solve for your two x-values. Those x-values are what x can't equal. Sorry, I sound like I'm talking in riddles lol. x^2+2x+3 = 0 (then use the quadratic formula and solve for x)

    • 2 years ago
  35. brinethery Group Title
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    That's okay!

    • 2 years ago
  36. brinethery Group Title
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    I don't think they'll ask you to find the domain of something with x's and y's. Or are they?

    • 2 years ago
  37. denise9423 Group Title
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    yes

    • 2 years ago
  38. denise9423 Group Title
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    no sorry

    • 2 years ago
  39. denise9423 Group Title
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    simplify

    • 2 years ago
  40. brinethery Group Title
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    I can help you on something like that, but first off is that denominator stuff making sense? Really sleep on that and try to remember it b/c it's super important for calculus.

    • 2 years ago
  41. denise9423 Group Title
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    -7xyy/28xxxxxy

    • 2 years ago
  42. brinethery Group Title
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    Okay well what multiples to 7 and 8 have in common? What can you divide them both by?

    • 2 years ago
  43. brinethery Group Title
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    I mean 28.

    • 2 years ago
  44. denise9423 Group Title
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    yes it does bc it will help me remember to put=0 so I can solve for x

    • 2 years ago
  45. brinethery Group Title
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    good :-)

    • 2 years ago
  46. denise9423 Group Title
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    4

    • 2 years ago
  47. brinethery Group Title
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    -7xyy/28xxxxxy You can divide the numerator and denominator by 7. Also, which has the smallest amount of x's, and then which one has the smallest amount of y's?

    • 2 years ago
  48. denise9423 Group Title
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    3x7=28

    • 2 years ago
  49. denise9423 Group Title
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    no 4x7=28

    • 2 years ago
  50. brinethery Group Title
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    The numerator has the smallest amount of x's. There is 1 of them. The denominator has the smallest amount of y's, which is 1 y. So we'll divide the numerator and denominator by 7. -1*x*y*y/4xxxxxy

    • 2 years ago
  51. denise9423 Group Title
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    bottom has 5 x's and the top has 2 y's

    • 2 years ago
  52. brinethery Group Title
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    We have to cancel out the smallest amount of x's. And we also cancel out the smallest amount of y's. So we have: -1*y/4xxxx I canceled out an x on the top and bottom. Then I canceled out a y on the top and bottom.

    • 2 years ago
  53. denise9423 Group Title
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    ok

    • 2 years ago
  54. denise9423 Group Title
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    sorry i have a 911 gotta chk out b back later thank you for all ur help god bless

    • 2 years ago
  55. brinethery Group Title
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    k

    • 2 years ago
  56. brinethery Group Title
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    Anyway, -1*y/4xxxx can be re-written as: -y/4x^4 See Paul, my favorite math teacher: (I swear by his notes) http://tutorial.math.lamar.edu/Classes/Alg/IntegerExponents.aspx

    • 2 years ago
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