A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

anonymous

  • 5 years ago

How can I solve using elimination and back substitution?

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

    can some of u just help me with my stereo one

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

    {4x-2y-4z=32 x-y+4z=-13 6x-4y+2z=14}

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

    I already know the first step is 4x-2y-4z=32 x-y-4z=-13

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

    5x-4y=19

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

    I become lost after this step

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

    Hello? Are u able youassist?

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

    solve one equation for some variable, then plug in into one of the other equations, then solve for one of the two variables. You then have one of your variable. Though I think it is easier to use Gaussian elimination.

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

    Gaussian elimination? Can you show me how that works?

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

    write the coefficients of each variable for each equation into a matrix like pattern and add or subtract rows from one another until you have the pattern: 100=a 010=b 001=c or 001=a 010=b 100=c

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

    Not really seeing how that will help me get the correct answer

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

    Its better because there is no substituting. You add and subtract rows until you end up with diagonal ones. If the one in the 'a' equation is in the x column, that is your x and so on.

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

    I can help you. When you substitute, you first want to solve for a single variable. So take your equation 4x-2y-4z=32. You can solve for x by adding 2y and 4z to the other side. It is then 4x=2y+4z+32. Then divide by 4 making it x=1/2y+z+8

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

    Now, you can plug that x into another equation. x-y-4z=-13 for instance. When you plug in what you've found for x, you'll only end up with z and y values in it. So (1/2y+z+8)-y-4z=-13

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

    I just used the parentheses to show what the equation was for x. Is this making sense?

  15. 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.