Quantcast

A community for students. Sign up today!

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

fari321

  • 2 years ago

One factor of 4x^3+15x^2-31x-30 is x-2. Find the other factors

  • This Question is Closed
  1. freewilly922
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    You could use long division or synthetic division. Your choice.

  2. fari321
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    how

  3. fari321
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    with long division

  4. freewilly922
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Well to start with you know that \[4x^2 \times (x-2) = 4x^3-8x^2\] so just like you would do long division with numbers you can also do it with variables like this. so \[ 4x^3-15x^2 -\bigg[4x^3-8x^2 \bigg]=-7x^2\] you drop the -31x like long division to get \[-7x^2 -31x\] and then divide this by (x-2) again \[-7x\times (x-2) = -7x^2 +14x\] and so on

  5. freewilly922
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    sorry the \[-15x^2 \] should be positive 15

  6. freewilly922
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    so \[4x^3+15x^2 -\bigg[4x^3-8x^2 \bigg]=23x^2\] \[23x\times (x-2) = 23x^2-46x\] \[23x^2-31x -\bigg[23x^2-46x\bigg]=+15x\] \[15\times(x-2)=15x-30\] \[+15x-30 -\bigg[15x-30 \bigg]=0\] so \[4x^3+15x^2-31x-30 \to (x-2)(4x^2+23x+15)\] and you can factor the rest... hopefully

  7. freewilly922
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Explaining how to do long division or synthetic division is a real pain on open study, I would suggest you take the time outside of this to study it from a book with examples. Or go online and search for a youtube video. It isn't hard.

  8. fari321
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    thank you

  9. 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.