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Math Help - Simultaneous Equations

  1. #1
    Member princess_anna57's Avatar
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    Smile Simultaneous Equations

    Solve:

    2x + 4 = 4
    3x - y = 1

    Solve:
    x - 2y = 7
    2x + y = 4

    Please give step by step instructions. Thank you.
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  2. #2
    Bar0n janvdl's Avatar
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    Meh
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    Quote Originally Posted by princess_anna57 View Post
    Solve:

    2x + 4 = 4
    3x - y = 1


    Please double check that you did not make a typo here.



    2x + 4 = 4
    2x = 4 - 4
    2x = 0
    x = 0

    We now know x = 0

    3x - y = 1
    3(0) - y = 1
    y = -1

    Thus:
    x = 0
    y = -1


    Solve:
    x - 2y = 7
    2x + y = 4


    x - 2y = 7
    x = 7 + 2y (Set this value for x into the second equation)

    2(7 + 2y) + y = 4
    14 + 4y + y = 4
    5y = -10
    y = -2

    Now we have a value for y. (y = -2)
    Set this value into the first equation.

    x -2(-2) = 7
    x + 4 = 7
    x = 3


    Please give step by step instructions. Thank you.
    Responses in red.
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  3. #3
    Member princess_anna57's Avatar
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    Thank you

    Nope, no typos in the equations. Thanks a lot.
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  4. #4
    Bar0n janvdl's Avatar
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    Quote Originally Posted by princess_anna57 View Post
    Nope, no typos in the equations. Thanks a lot.
    You are welcome
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