A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

anonymous

  • one year ago

10. Find the set values of k for which the line y=kx-4 intersects the curve y=x^2-2x at two distinct points. Pleas help, I don't know what do do with this question. I tried solving it simultaneously and the using b^2-4ac but that didn't get me anywhere.

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

    you tried? let me try the same thing, kx -4 = x^2 -2x x^2 - (k+2)x + 4 = 0 A = 1, B = -(k+2) , C = 4 you got same values?

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

    Oh, no not at all. I didn't even end up getting any values.

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

    i though you said you used b^2 -4ac what values of a,b,c did u get?

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

    for 2 distinct points b^2 -4ac must be > 0

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

    [-(k+2)]^2 - 4 > 0

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

    or (k+2)^2 > 4

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

    I will send a picture of my working out.

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

    sorry [{-(k+2)}^2-4*1*4]

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

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

    So after k^2>-4k-12 I didn't know what to do

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

    oh yeah, \((k+2)^2 -16 > 0 \\ (k+2)^2 >16\) keep this as is and take square root on both sides...

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

    \[\left( k+2 \right)^2>4^2,\left| k+2 \right|>4,k+2<-4,k<-6~or~k+2>4,k>2\]

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

    Oh I see!

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

    Ok I am getting the right numbers now (2 and -6) but the symbols are wrong. I got k>2 and k>-6 but it actually k>2 and k<-6

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

    |k+2| > 4 k+2 > 4 or k+2 < -4

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

    it like if |a| >b then a >b or a < -b

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

    So the symbols switch when you take the square root of everything? Depending on if you are working with the positive or negative?

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

    symbols switch when you multiply a negative on both sides

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

    in case of |a| > b |dw:1442155794098:dw|

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

    Ok, I think I understand now. Thank you very much! Your explanations really helped me!

  21. 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.