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chris65

slove equations and put it into a matrices 4t-5r=21 3t-7r=18

  • one year ago
  • one year ago

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  1. lilg132
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    4t - 5r = 21 (multiply all by 7) 3t - 7r = 18 (multiply all by -5) 28t - 35r = 147 -15t + 35r = 90 add the two equations together 13t =237 t = 18.230769230769230769230769230769 4(18.230769230769230769230769230769) - 5r = 21 72.923076923076923076923076923077 - 5r = 21 72.923076923076923076923076923077 - 21 = 5r 51.923076923076923076923076923077 = 5r 10.384615384615384615384615384615 = r not sure if this is right

    • one year ago
  2. chris65
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    i got the answer of t=57/13 and r=-9/13 but i have to put it into a matrices

    • one year ago
  3. lilg132
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    lol damn i had it right the first time

    • one year ago
  4. lilg132
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    let me write it out again

    • one year ago
  5. chris65
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    ok but i dont know how to put it into a matrix

    • one year ago
  6. lilg132
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    4t - 5r = 21 3t - 7r = 18 4t = 21 + 5r divide everything by 4 t = 5.25 + 1.25r 3(5.25 + 1.25r) - 7r = 18 15.75 + 3.75r - 7r = 18 15.75 - 18 = 7r - 3.75r -2.25 = 3.25r -2.25 / 3.25 = 3.25r / 3.25 -9/13 = r 4t - 5(-9/13) = 21 4t + 45/13 = 21 4t = 21 - 45/13 4t = 228/13 4t / 4 = (228/13)/4 t = 57/13

    • one year ago
  7. lilg132
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    ok let me work out how to put into matrix

    • one year ago
  8. chris65
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    ok i got all that i just dont no how to make a matrix out of that

    • one year ago
  9. lilg132
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    no idea with matrixes going to have to ask someone else sorry

    • one year ago
  10. lilg132
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    im out of here bye

    • one year ago
  11. AriPotta
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    |dw:1354243922660:dw|

    • one year ago
  12. chris65
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    |dw:1354244060647:dw|

    • one year ago
  13. chris65
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    thats what i have to put my answer in

    • one year ago
  14. AriPotta
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    only two sets of brackets?

    • one year ago
  15. chris65
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    yes

    • one year ago
  16. AriPotta
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    are they only looking for Dt and Dr?

    • one year ago
  17. chris65
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    yes

    • one year ago
  18. AriPotta
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    |dw:1354244183257:dw| there. lol

    • one year ago
  19. chris65
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    lol

    • one year ago
  20. chris65
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    ok i got another problem for ya

    • one year ago
  21. AriPotta
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    mer.

    • one year ago
  22. chris65
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    3x-z=4 x+y+7z=0 3x+y-z=4 and x=148/119 y=16/17 z=1

    • one year ago
  23. chris65
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    that also has to be into a matrices

    • one year ago
  24. AriPotta
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    oh. idk about 3 variable ones. i'm sorry :/

    • one year ago
  25. chris65
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    ok thanks

    • one year ago
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