Quantcast

Got Homework?

Connect with other students for help. It's a free community.

  • across
    MIT Grad Student
    Online now
  • laura*
    Helped 1,000 students
    Online now
  • Hero
    College Math Guru
    Online now

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

dddan

please help!; how do you find the solutions for x^4-x^2-12=0

  • one year ago
  • one year ago

  • This Question is Closed
  1. tejasree
    Best Response
    You've already chosen the best response.
    Medals 1

    Factor it out!

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

    (x^2 - 4)(x^2 + 3) = 0

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

    i did and got 0,3,-4

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

    i just want to see if im right

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

    no!

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

    x^2 - 4 = 0 (x-2)(x+2) = 0 x=2,-2

    • one year ago
  7. cwrw238
    Best Response
    You've already chosen the best response.
    Medals 0

    let y = x^2 then y^2 - y -12 = 0 can you solve this?

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

    wait there are more solutions

    • one year ago
  9. cwrw238
    Best Response
    You've already chosen the best response.
    Medals 0

    yup there will be 4 solution because the degree of the equation is 4

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

    x^2 + 3 = 0 x^2 = -3 \[x = i \sqrt{3}, -i \sqrt{3}\]

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

    the solutions are: \[x = 2, -2, i \sqrt{3}, -i \sqrt{3}\]

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

    am I correct @cwrw238

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

    i understand why there 4 solutions but where did you get them from?

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

    First we factored them out, didnt we? then we set each factor equal to zero

    • one year ago
  15. jim_thompson5910
    Best Response
    You've already chosen the best response.
    Medals 0

    It might be easier to let z = x^2 so z^2 = x^4 which allows us to go from x^4-x^2-12=0 to z^2-z-12=0

    • one year ago
  16. jim_thompson5910
    Best Response
    You've already chosen the best response.
    Medals 0

    solve z^2-z-12=0 and keep in mind that z = x^2 so you can solve for x

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

    o because it x^2=3 its the square root plus i right

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

    ok i got it - thank you so much guys

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

    there you go @jim_thompson5910 :)

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

    thank you! :)

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

    this site is really helpful: mathway.com

    • one year ago
  22. cwrw238
    Best Response
    You've already chosen the best response.
    Medals 0

    @tegasree - u r correct

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

    thank you! :)

    • one year ago
    • Attachments:

See more questions >>>

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.