A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

Barrelracing

  • one year ago

When looking at the rational function f of x equals the quantity x minus one times the quantity x plus two times the quantity x plus four all divided by the quantity x plus one times the quantity x minus two times the quantity x minus four, Bella and Edward have two different thoughts. Bella says that the function is defined at x = –1, x = 2, and x = 4. Edward says that the function is undefined at those x values. Who is correct? Justify your reasoning.

  • This Question is Closed
  1. Barrelracing
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    @jim_thompson5910

  2. Barrelracing
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    @freckles

  3. jim_thompson5910
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    ` f of x equals the quantity x minus one times the quantity x plus two times the quantity x plus four all divided by the quantity x plus one times the quantity x minus two times the quantity x minus four` what a mess... hopefully I translated the word problem into the proper function \[\Large f(x) = \frac{(x-1)(x+2)(x+4)}{(x+1)(x-2)(x-4)}\] let me know if I did or not

  4. Barrelracing
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    yes you did

  5. jim_thompson5910
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    ok great

  6. jim_thompson5910
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    `Bella says that the function is defined at x = –1, x = 2, and x = 4` let's check this claim. If we were to replace EVERY x with a value like x = 4, then... \[\Large f(x) = \frac{(x-1)(x+2)(x+4)}{(x+1)(x-2)(x-4)}\] \[\Large f(4) = \frac{(4-1)(4+2)(4+4)}{(4+1)(4-2)(4-4)}\] \[\Large f(4) = \frac{(3)(6)(8)}{(5)(2)(0)}\] \[\Large f(4) = \frac{144}{0}\] \[\Large f(4) = \text{Undefined}\] the result is undefined because we cannot divide by zero. We can't have 0 in the denominator

  7. jim_thompson5910
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    `Bella says that the function is defined at x = –1, x = 2, and x = 4` so Bella is wrong. At least about the `x=4` part. I recommend you check `x=-1` and `x=2`

  8. Barrelracing
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    ok thank you

  9. jim_thompson5910
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    no problem

  10. Barrelracing
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    the rest are not undefined

  11. jim_thompson5910
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    correct,x=-1 and x=2 are also undefined because they make the denominator 0

  12. jim_thompson5910
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    oh wait, you should say "the rest are undefined" or "the rest are not defined"

  13. Barrelracing
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    i got f(-1)=-4 and f(2)= 11

  14. jim_thompson5910
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    you did something wrong

  15. Barrelracing
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    f(-1) = (-1 - 1)(-1 + 2)(-1 + 4)/ (-1 + 1)(-1 - 2)(-1 - 4) = -2 + 1 + 3/ 0 - 3 - 5 = 2/-8 f(-1) = -4

  16. Barrelracing
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    f(2) = (2 - 1)(2 + 2)(2 + 4)/ (2 + 1)(2 - 2)(2 - 4) = 1 + 4 + 6/ 3 + 0 - 2 = 11/1 = 11

  17. Barrelracing
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    are you gonna help me still? @jim_thompson5910

  18. jim_thompson5910
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    sorry my notification thing isn't working properly

  19. Barrelracing
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    thats ok

  20. jim_thompson5910
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    (-1 + 1)(-1 - 2)(-1 - 4) = 0*(-3)*(-5) = 0 is in the denominator

  21. jim_thompson5910
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    the parenthesis next to each other means multiply

  22. jim_thompson5910
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    make sense?

  23. Barrelracing
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    ohhh ok thank you so much for the help.

  24. jim_thompson5910
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    no problem

  25. Not the answer you are looking for?
    Search for more explanations.

    • Attachments:

Ask your own question

Sign Up
Find more explanations on OpenStudy
Privacy Policy

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.