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

NY,NY Group Title

HELPPP ME STUDY! solve algebraically for a and b and check: 3a+5b=4 4a+3b=-2

  • one year ago
  • one year ago

  • This Question is Closed
  1. goformit100 Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    You can use Matrix method for solving these two equations simultaneously

    • one year ago
  2. NY,NY Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    i only know substitution, graphing, and elimination method and those are the only methods i can use.

    • one year ago
  3. darkprince14 Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    try eliminating either a or b

    • one year ago
  4. darkprince14 Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    If you're looking for the point of intersection or the solution to those two then that's helpful if not, sorry, i have no clue what to do next ..

    • one year ago
  5. NY,NY Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    i need to find the value of a and b, not find the solution. like get a or b by itself.

    • one year ago
  6. darkprince14 Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    how about let a = 0 or something like that...

    • one year ago
  7. NY,NY Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    not working :(

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

    Here's the plan; try to "get a in terms of b" (or "b in terms of a"). Really, I mean try to solve for a, so that it equals something that involves b (or solve for b so that it equals something that involves a).

    • one year ago
  9. NY,NY Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    yeah, i know. but how do i do that?

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

    You can look at either equation, and solve for either variable. It's up to you!

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

    It's all fair game in this problem. So pick and equation and pick a variable to solve for!

    • one year ago
  12. NY,NY Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    ok, 3a+5b=4. let's solve for a.

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

    Okay, you start! I'll watch.

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

    Unless you want to workon it together now; we can do that.

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

    work on*

    • one year ago
  16. NY,NY Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    yeah, let's work on it together.

    • one year ago
  17. theEric Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    Alright. When equations aren't too complex, a great starting point is getting the terms containing variable you're solving for, a, on the opposite side of all the other terms. So look at 3a+5b=4. Which term (containing a) do we want to it's own side?

    • one year ago
  18. NY,NY Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    3a.

    • one year ago
  19. NY,NY Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    3a= -5b+4

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

    I agree! And it's with 5b, which we need to get rid of. And it appears you know how to do that! Good! So now a is still stuck with something; it's being multiplied by 3! So can you fix that, too?

    • one year ago
  21. NY,NY Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    \[a= \frac{ 5b+4 }{ 3 }\]

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

    close! You forgot your sign of 5b! You had it right before! I'm guessing you were distracted by Open Study's fancy equation thing, but I don't know.

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

    so a=(-5b+4)/3

    • one year ago
  24. NY,NY Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    oopssss. i meant -5b*

    • one year ago
  25. NY,NY Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    yeahh

    • one year ago
  26. theEric Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    \[a=\frac{-5b+4}{3}\]Haha, that's fine! So we solved for a in that one equation, 3a+5b=4. a is always a is always (-5b+4)/3. So we can substitute it into another a's place. Try it in the other equation, 4a+3b=-2. the a will be replaced and the only variable in the equation will be b. The we can solve for b!

    • one year ago
  27. theEric Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    So, start by substitution!

    • one year ago
  28. NY,NY Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    -20b+16/3+3b=-2

    • one year ago
  29. theEric Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    Make sure you type (-20b+16)/3 + 3b = -2 ! I see you factored correctly, but the way you wrote it it didn't look like it was all divided by 3, though it really was! :)

    • one year ago
  30. theEric Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    So\[\frac{-20b+16}{3}+3b = -2\]

    • one year ago
  31. NY,NY Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    multiply by 3?

    • one year ago
  32. theEric Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    Yeah, I'd do that!

    • one year ago
  33. theEric Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    Just so that left-most b isn't divided by it.

    • one year ago
  34. NY,NY Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    -20b+16+3b=-6?

    • one year ago
  35. theEric Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    So\[3(\frac{-20b+16}{3}+3b)=3(-2)\]

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

    Common mistake! Don't worry! You just have to remember to multiply each entire side by 3. That way you're doing the same thing to each side, so that the two new sides will still be equal.

    • one year ago
  37. NY,NY Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    i multiplied by 3 to -20b + 16 so that canceled the 3 out, and then i multiplied the -2 by 3, giving -6. what i do wrong?

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

    You have to multiply 3b by 3 as well!

    • one year ago
  39. theEric Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    it becomes 9b!

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

    So -20b+16+9b=-6 :)

    • one year ago
  41. theEric Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    I'm sure you'll see it soon.

    • one year ago
  42. NY,NY Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    ohhh. wow, yeah. b=2?

    • one year ago
  43. theEric Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    -20b+16+9b=-6 -20b+9b=-22 -11b=-22 22=11b 22/11=b 2=b Yeah!

    • one year ago
  44. theEric Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    I had to work it out to check, but we got the same thing.

    • one year ago
  45. NY,NY Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    yay :D thanks eric :D yur awesome :D

    • one year ago
  46. theEric Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    Sorry for the wait, Open Study glitched :P Recap, we solved for "a in terms of b" and we solved for b. Now we know b and can now solve for a!

    • one year ago
  47. theEric Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    My pleasure! Thank you for doing your part! You did great!

    • one year ago
  48. theEric Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    \[a=\frac{-5b+4}{3}=\frac{-5(2)+4}{3}\] and compute... finale!

    • one year ago
  49. NY,NY Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    thanks :D

    • one year ago
  50. NY,NY Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    i just hope i do good on the quiz tomorrow...

    • one year ago
  51. NY,NY Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    a=-10+4/3 a=-6/3 a=-2

    • one year ago
  52. theEric Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    My pleasure. Did you get a = 2?

    • one year ago
  53. theEric Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    Best of luck! Tag me in any other questions you have, or you can ask them here. But the most important thing in these an dmany other math problems is planning! Knowing what you will do. This technique we used is good for this situation.

    • one year ago
  54. theEric Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    Haha!! Caught me! -2 ! :D

    • one year ago
  55. theEric Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    Serves me right for trying to do it in my head.

    • one year ago
  56. theEric Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    My responses are out of order. Open Stud is scrambled, it seems.

    • one year ago
  57. NY,NY Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    yeah. open study is being really laggy today. if i can just finish up my science homework, ill bring up some more questions to study with. thanks again :D and bye for now.

    • one year ago
  58. theEric Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    I'm glad it's not just me! No problem. Good luck with everything!

    • 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.