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Math Help - Solving for x and y, etc...

  1. #1
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    Solving for x and y, etc...

    Ok I am confused with these problems:

    Solving for X and Y using substitution:

    1. 2x+y=4
    3x-y=6

    2. 3x+15y=3
    2x-5y=-28

    3. 4x-5y=0
    8x-10y+15

    Solving for X and Y using linear addition:

    4.5x-7y=2
    3x=4y

    5.10x+10y=40-5x
    9x+2y=32-6y

    6. 2x=8y+24
    3x+5y=2
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  2. #2
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    Quote Originally Posted by peachgal View Post
    Ok I am confused with these problems:

    Solving for X and Y using substitution:

    1. 2x+y=4
    3x-y=6
    You have two equations and two unknowns. Start with the first equation: 2x+y=4. Solve for y.

    2x+y=4
    y=4-2x

    Now take this and plug in "4-2x" for "y" in the second equation.

    3x-y=6
    3x-(4-2x)=6
    3x-4+2x=6
    5x-4=6
    5x=10
    x=2

    Now that we have found x, plug "2" in for "x" in either the first or second equation to find y.

    2x+y=4
    2(2)+y=4
    4+y=4
    y=0

    So the final answer is x=0, y=2. If you plug in these numbers to both equations you can verify they are correct.
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