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

katie2212

Use elimination to solve the system. What is the value of x? 4x + 7y = -14 and 8x + 5y = 8

  • one year ago
  • one year ago

  • This Question is Closed
  1. jim_thompson5910
    Best Response
    You've already chosen the best response.
    Medals 1

    Hint: Multiply everything in the first equation by -2 to go from 4x + 7y = -14 to -8x - 14y = 28

    • one year ago
  2. jim_thompson5910
    Best Response
    You've already chosen the best response.
    Medals 1

    So you now have the two equations -8x - 14y = 28 8x + 5y = 8

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

    That's solving for x first and then plugging it back to get y. I thought that the OP wanted to do it from that one step.

    • one year ago
  4. jim_thompson5910
    Best Response
    You've already chosen the best response.
    Medals 1

    you can go a number of ways, you can multiply the top equation by 5 and the bottom equation by -7, then add

    • one year ago
  5. katie2212
    Best Response
    You've already chosen the best response.
    Medals 0

    im just getting more confused

    • one year ago
  6. jefferyflow123go
    Best Response
    You've already chosen the best response.
    Medals 0

    I believe the answer is -14.

    • one year ago
  7. katie2212
    Best Response
    You've already chosen the best response.
    Medals 0

    these are the options. 3.5 -1.5 8 -4

    • one year ago
  8. jefferyflow123go
    Best Response
    You've already chosen the best response.
    Medals 0

    Oh then i bet the answer is -5

    • one year ago
  9. jim_thompson5910
    Best Response
    You've already chosen the best response.
    Medals 1

    Do you see how I went from 4x + 7y = -14 to -8x - 14y = 28

    • one year ago
  10. jim_thompson5910
    Best Response
    You've already chosen the best response.
    Medals 1

    it's not -5

    • one year ago
  11. jim_thompson5910
    Best Response
    You've already chosen the best response.
    Medals 1

    please don't give away the (incorrect) answer

    • one year ago
  12. jefferyflow123go
    Best Response
    You've already chosen the best response.
    Medals 0

    sorry, if you would just give her the right answer, i would be able to go on with my day. As would she

    • one year ago
  13. jim_thompson5910
    Best Response
    You've already chosen the best response.
    Medals 1

    I'm providing hints and trying to walk her through it (without giving it all away)

    • one year ago
  14. jefferyflow123go
    Best Response
    You've already chosen the best response.
    Medals 0

    No matter how many hints your provide she doesn't care. she just wants the answer

    • one year ago
  15. jim_thompson5910
    Best Response
    You've already chosen the best response.
    Medals 1

    well that's not what this site is for, I'm sry

    • one year ago
  16. jim_thompson5910
    Best Response
    You've already chosen the best response.
    Medals 1

    if you keep this behavior up jefferyflow123go you will be reported (and possibly suspended/banned)

    • one year ago
  17. katie2212
    Best Response
    You've already chosen the best response.
    Medals 0

    its hard for me too understand..im trying. i learn better in a class room thats why i am having trouble with my online class

    • one year ago
  18. jim_thompson5910
    Best Response
    You've already chosen the best response.
    Medals 1

    its ok, you don't have to understand everything at once katie2212

    • one year ago
  19. katie2212
    Best Response
    You've already chosen the best response.
    Medals 0

    but i have to understand if i want to finishe this exam.

    • one year ago
  20. jefferyflow123go
    Best Response
    You've already chosen the best response.
    Medals 0

    Sorry for hekping. My mom always taught me to hekp and have pride in my work, so trying to be of assistance. I didn;t realize that you can be the only genious here. If you were that smart you'd know that she doesn't understand your hints and just wants the answer.

    • one year ago
  21. jim_thompson5910
    Best Response
    You've already chosen the best response.
    Medals 1

    that's not helping though, you may think it is...but it's not

    • one year ago
  22. jim_thompson5910
    Best Response
    You've already chosen the best response.
    Medals 1

    if you want, you can provide the steps so she can learn from them

    • one year ago
  23. katie2212
    Best Response
    You've already chosen the best response.
    Medals 0

    okay will you guys please stop arguing and just help me!

    • one year ago
  24. jim_thompson5910
    Best Response
    You've already chosen the best response.
    Medals 1

    ok I'll give steps on this one and hopefully it will be enough to answer similar ones, sound good?

    • one year ago
  25. jefferyflow123go
    Best Response
    You've already chosen the best response.
    Medals 0

    IS your refrigderator running ? IF SO GO CATCH IT

    • one year ago
  26. katie2212
    Best Response
    You've already chosen the best response.
    Medals 0

    yes thank you

    • one year ago
  27. jefferyflow123go
    Best Response
    You've already chosen the best response.
    Medals 0

    My momma once told me, a fast runna' is the best runnna'

    • one year ago
  28. katie2212
    Best Response
    You've already chosen the best response.
    Medals 0

    jeffery if youre not going to help please get out.

    • one year ago
  29. jefferyflow123go
    Best Response
    You've already chosen the best response.
    Medals 0

    BUT IM JUST TRYNA HELP YOU. ILL CATCH YOUR FRIDGE FR YOU.

    • one year ago
  30. jefferyflow123go
    Best Response
    You've already chosen the best response.
    Medals 0

    What did the bison say to his son when he left for college? Bi-son

    • one year ago
  31. jim_thompson5910
    Best Response
    You've already chosen the best response.
    Medals 1

    4x + 7y = -14 ... Start with the first equation -2(4x + 7y) = -2*(-14) ... Multiply both sides by -2 -8x - 14y = 28 ... Distribute and multiply --------------------- So 4x + 7y = -14 is the same as -8x - 14y = 28 --------------------- This means that the system 4x + 7y = -14 8x + 5y = 8 becomes -8x - 14y = 28 8x + 5y = 8 Now add the two equations: -8x - 14y = 28 8x + 5y = 8 -------------- 0x - 9y = 36 which means that -9y = 36 Solve for y to get -9y = 36 y = 36/(-9) y = -4 Now that we know that y = -4, we can use this to find x. Pick on any equation, plug in y = -4 and solve for x 4x + 7y = -14 4x + 7(-4) = -14 4x - 28 = -14 4x = -14 + 28 4x = 14 x = 14/4 x = 7/2 x = 3.5 So the value of x is x = 3.5

    • one year ago
  32. jefferyflow123go
    Best Response
    You've already chosen the best response.
    Medals 0

    IM SO PUN-NY

    • one year ago
  33. jefferyflow123go
    Best Response
    You've already chosen the best response.
    Medals 0

    IM A MaTH WIZ

    • one year ago
  34. katie2212
    Best Response
    You've already chosen the best response.
    Medals 0

    Thank you Jim

    • one year ago
  35. jefferyflow123go
    Best Response
    You've already chosen the best response.
    Medals 0

    yanno wizard like Harry Potter

    • one year ago
  36. jim_thompson5910
    Best Response
    You've already chosen the best response.
    Medals 1

    The idea here is to get the x coefficients equal and opposite. Then you add the equations. Doing so will cancel out the x terms so you can solve for y

    • one year ago
  37. jim_thompson5910
    Best Response
    You've already chosen the best response.
    Medals 1

    then you use that value of y to find x

    • one year ago
  38. jim_thompson5910
    Best Response
    You've already chosen the best response.
    Medals 1

    you've been reported jefferyflow123go, have a nice day

    • one year ago
  39. jefferyflow123go
    Best Response
    You've already chosen the best response.
    Medals 0

    you too good sir(:

    • one year ago
  40. jim_thompson5910
    Best Response
    You've already chosen the best response.
    Medals 1

    good luck with that one, I don't spam and harass others so your claim will be without merit

    • 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.