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NY,NY Group Title

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

  • 2 years ago
  • 2 years ago

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  1. goformit100 Group Title
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    You can use Matrix method for solving these two equations simultaneously

    • 2 years ago
  2. NY,NY Group Title
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    i only know substitution, graphing, and elimination method and those are the only methods i can use.

    • 2 years ago
  3. darkprince14 Group Title
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    try eliminating either a or b

    • 2 years ago
  4. darkprince14 Group Title
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    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 ..

    • 2 years ago
  5. NY,NY Group Title
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    i need to find the value of a and b, not find the solution. like get a or b by itself.

    • 2 years ago
  6. darkprince14 Group Title
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    how about let a = 0 or something like that...

    • 2 years ago
  7. NY,NY Group Title
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    not working :(

    • 2 years ago
  8. theEric Group Title
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    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).

    • 2 years ago
  9. NY,NY Group Title
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    yeah, i know. but how do i do that?

    • 2 years ago
  10. theEric Group Title
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    You can look at either equation, and solve for either variable. It's up to you!

    • 2 years ago
  11. theEric Group Title
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    It's all fair game in this problem. So pick and equation and pick a variable to solve for!

    • 2 years ago
  12. NY,NY Group Title
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    ok, 3a+5b=4. let's solve for a.

    • 2 years ago
  13. theEric Group Title
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    Okay, you start! I'll watch.

    • 2 years ago
  14. theEric Group Title
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    Unless you want to workon it together now; we can do that.

    • 2 years ago
  15. theEric Group Title
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    work on*

    • 2 years ago
  16. NY,NY Group Title
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    yeah, let's work on it together.

    • 2 years ago
  17. theEric Group Title
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    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?

    • 2 years ago
  18. NY,NY Group Title
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    3a.

    • 2 years ago
  19. NY,NY Group Title
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    3a= -5b+4

    • 2 years ago
  20. theEric Group Title
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    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?

    • 2 years ago
  21. NY,NY Group Title
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    \[a= \frac{ 5b+4 }{ 3 }\]

    • 2 years ago
  22. theEric Group Title
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    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.

    • 2 years ago
  23. theEric Group Title
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    so a=(-5b+4)/3

    • 2 years ago
  24. NY,NY Group Title
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    oopssss. i meant -5b*

    • 2 years ago
  25. NY,NY Group Title
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    yeahh

    • 2 years ago
  26. theEric Group Title
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    \[a=\frac{-5b+4}{3}\]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!

    • 2 years ago
  27. theEric Group Title
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    So, start by substitution!

    • 2 years ago
  28. NY,NY Group Title
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    -20b+16/3+3b=-2

    • 2 years ago
  29. theEric Group Title
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    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! :)

    • 2 years ago
  30. theEric Group Title
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    So\[\frac{-20b+16}{3}+3b = -2\]

    • 2 years ago
  31. NY,NY Group Title
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    multiply by 3?

    • 2 years ago
  32. theEric Group Title
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    Yeah, I'd do that!

    • 2 years ago
  33. theEric Group Title
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    Just so that left-most b isn't divided by it.

    • 2 years ago
  34. NY,NY Group Title
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    -20b+16+3b=-6?

    • 2 years ago
  35. theEric Group Title
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    So\[3(\frac{-20b+16}{3}+3b)=3(-2)\]

    • 2 years ago
  36. theEric Group Title
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    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.

    • 2 years ago
  37. NY,NY Group Title
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    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?

    • 2 years ago
  38. theEric Group Title
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    You have to multiply 3b by 3 as well!

    • 2 years ago
  39. theEric Group Title
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    it becomes 9b!

    • 2 years ago
  40. theEric Group Title
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    So -20b+16+9b=-6 :)

    • 2 years ago
  41. theEric Group Title
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    I'm sure you'll see it soon.

    • 2 years ago
  42. NY,NY Group Title
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    ohhh. wow, yeah. b=2?

    • 2 years ago
  43. theEric Group Title
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    -20b+16+9b=-6 -20b+9b=-22 -11b=-22 22=11b 22/11=b 2=b Yeah!

    • 2 years ago
  44. theEric Group Title
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    I had to work it out to check, but we got the same thing.

    • 2 years ago
  45. NY,NY Group Title
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    yay :D thanks eric :D yur awesome :D

    • 2 years ago
  46. theEric Group Title
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    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!

    • 2 years ago
  47. theEric Group Title
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    My pleasure! Thank you for doing your part! You did great!

    • 2 years ago
  48. theEric Group Title
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    \[a=\frac{-5b+4}{3}=\frac{-5(2)+4}{3}\] and compute... finale!

    • 2 years ago
  49. NY,NY Group Title
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    thanks :D

    • 2 years ago
  50. NY,NY Group Title
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    i just hope i do good on the quiz tomorrow...

    • 2 years ago
  51. NY,NY Group Title
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    a=-10+4/3 a=-6/3 a=-2

    • 2 years ago
  52. theEric Group Title
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    My pleasure. Did you get a = 2?

    • 2 years ago
  53. theEric Group Title
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    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.

    • 2 years ago
  54. theEric Group Title
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    Haha!! Caught me! -2 ! :D

    • 2 years ago
  55. theEric Group Title
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    Serves me right for trying to do it in my head.

    • 2 years ago
  56. theEric Group Title
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    My responses are out of order. Open Stud is scrambled, it seems.

    • 2 years ago
  57. NY,NY Group Title
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    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.

    • 2 years ago
  58. theEric Group Title
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    I'm glad it's not just me! No problem. Good luck with everything!

    • 2 years ago
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