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sommersquid

  • 3 years ago

What is the value of the x variable in the solution to the following system of equations? 7x - 2y = 21 4x + y = 57

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  1. iheartfood
    • 3 years ago
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    ummm is this algebra 2?

  2. sommersquid
    • 3 years ago
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    algebra 1, 2nd year taking it again

  3. sommersquid
    • 3 years ago
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    once i find the y , i put it in the the first equation right?

  4. iheartfood
    • 3 years ago
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    I think so... i asked somebody if they could come and help since I need to understand this better as well since i sort of forgot haha :)

  5. iheartfood
    • 3 years ago
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    sorry hold on lemme see if that person will come... ;/

  6. sommersquid
    • 3 years ago
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    okay thank you (:

  7. iheartfood
    • 3 years ago
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    Hi @jim_thompson5910 thanks for coming :) I also do not understand this 100% haha :) u got my message then i take it? :)

  8. jim_thompson5910
    • 3 years ago
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    double everything in the second equation to get 8x + 2y = 114

  9. iheartfood
    • 3 years ago
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    sorry (email)

  10. iheartfood
    • 3 years ago
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    and hi @apoorvk thanks for coming also!!! i appreciate it :)

  11. apoorvk
    • 3 years ago
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    ohkay, @iheartfood - go on and post what you would have done in this problem, and don't worry if it's right or wrong.. :)

  12. jim_thompson5910
    • 3 years ago
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    Now add the two equations 7x - 2y = 21 8x + 2y = 114 -------------- 15x + 0y = 135 Now solve 15x = 135 for x

  13. iheartfood
    • 3 years ago
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    well i know you're supposed to solve for one, but i did not know you could do that (what @jim_thompson5910 wrote.... so that is another way you can do it??

  14. iheartfood
    • 3 years ago
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    is that how you do it?? simplify it into one larger equation??

  15. jim_thompson5910
    • 3 years ago
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    that's one way to do it, there is more than one way

  16. iheartfood
    • 3 years ago
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    okay, what's another way to do it?? i think i remember that you can solve one equation and then plug it in but i couldn't do it for this one... ;/

  17. jim_thompson5910
    • 3 years ago
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    you isolate one variable in terms of the other then you substitute 4x + y = 57 y = 57 - 4x ------------------ 7x - 2y = 21 7x - 2(57-4x) = 21 Now solve for x

  18. sommersquid
    • 3 years ago
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    x = 9 for my problem right? (:

  19. iheartfood
    • 3 years ago
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    oh okay cool :) soooo x=45??

  20. jim_thompson5910
    • 3 years ago
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    you are correct, the answer to the first piece is x = 9

  21. iheartfood
    • 3 years ago
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    oops my bad nvm lol

  22. jim_thompson5910
    • 3 years ago
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    hmm how did you get x = 45?

  23. jim_thompson5910
    • 3 years ago
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    now that you know that x = 9, use this to find y

  24. iheartfood
    • 3 years ago
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    sorry by bad... lol it's 9 sorry!!

  25. iheartfood
    • 3 years ago
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    sooo you plug it in right??

  26. iheartfood
    • 3 years ago
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    so y=21 ???? and x=9 ???

  27. jim_thompson5910
    • 3 years ago
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    yes, pick any equation dealing with y and plug in x = 9 7x - 2y = 21 7(9) - 2y = 21 Solve for y

  28. jim_thompson5910
    • 3 years ago
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    and yes, y = 21

  29. iheartfood
    • 3 years ago
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    oh i used the second equation.. haha but it works both ways :) u get the same answer for both right?

  30. jim_thompson5910
    • 3 years ago
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    oh the question was just "What is the value of the x variable in the solution to the following system of equations?" so they just want x Usually, they'll want both x and y

  31. jim_thompson5910
    • 3 years ago
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    yes either equation works

  32. iheartfood
    • 3 years ago
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    oh okay cool! thanks!! i totally understand it now... :) what a refresher!! And @sommersquid did that help??? And thanks again for coming @jim_thompson5910 :)

  33. sommersquid
    • 3 years ago
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    yesss, it really did (: i just needed help with the second step but i got it now (: thank you so much everyone

  34. jim_thompson5910
    • 3 years ago
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    yw

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