Quantcast

A community for students. Sign up today!

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

headge

  • 2 years ago

You are given that f(x) = x^3 - 19x + 30 1.) Calculate f(0) and f(3). Hence write down a factor of f(x). Thanks.

  • This Question is Closed
  1. headge
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    @amistre64 @Hero

  2. mukushla
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    can u evaluate f(0) and f(3) ?

  3. headge
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    What does evaluate mean?

  4. mukushla
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    calculate-compute-

  5. headge
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Hmmm hang on. Do you mean put them into the f(X)= thing?

  6. Hero
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Evaluate means to do this: f(x) = x^3 - 19x + 30 f(0) = (0)^3 - 19(0) + 30 = ? f(3) = (3)^3 - 19(3) + 30 = ?

  7. headge
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Yes ok Ill have a go at that and tell you what I got thanks.

  8. headge
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Right for f(0) I got 30 and the next one 0

  9. Hero
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    f(3) = 0 Are you sure?

  10. headge
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Ill do it again

  11. headge
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Did it again and got 0 again.

  12. Hero
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    f(3) = (3)^3 - 19(3) + 30 = 27 - 57 + 30 = 30 + 27 - 57 = 57 - 57 = 0 OK

  13. headge
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Yes!! So now I have two more questions. Are you up for helping?

  14. headge
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Wait what is the 'hence write down the factor of f(x)' bit?

  15. headge
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    @nincompoop

  16. headge
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    @estudier

  17. Hero
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    If you calculated f(3) = 0, then (x-3) is a factor

  18. headge
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    :) I remeber that now. The 0 ones it is.

  19. headge
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    (ii) Find p and q such that f(x) = (x-2)(x^2 + px +q). How does one go about this?

  20. headge
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    @karatechopper @myininaya

  21. headge
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    @Coolsector

  22. Coolsector
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    (x-2)(x^2 + px +q) = x^3 +px^2 +qx -2x^2 -2px -2q = x^3 +(p-2)x^2 +(q-2p)x - 2q and the orig is x^3 - 19x + 30 so we know that p-2 should be 0 and q-2p should be -19 and -2q should be 30 can you answer now ?

  23. headge
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Wait....Where has that big line came from? ohhh you timesed out the brackets! Ok wait a min.

  24. headge
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    I get it up to when you start saying the so we know p-2=0 bit. I dont know how we know that.

  25. Coolsector
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    ok you see we have a term (p-2)x^2 but in the general equation we dont have x^2 at all .. so we have to make it disappear .. we do this by saying p-2 = 0

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

    • Attachments:

Ask your own question

Ask a Question
Find more explanations on OpenStudy

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.