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Math Help - system of eauations

  1. #1
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    system of eauations

    im stumbed some help please
    7x=4y=-2
    10x-3y=32

    i need to use subsitution for this i dont get it? explain?
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  2. #2
    A riddle wrapped in an enigma
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    Quote Originally Posted by mcinnes View Post
    im stumbed some help please
    7x=4y=-2
    10x-3y=32

    i need to use subsitution for this i dont get it? explain?
    You have a typo in your first equation.
    Not a real good candidate for substitution, but if you have to.....

    Step 1: Solve the first equation for x or y (whichever is easier).

    Step 2: Substitute that into your second equation to solve for your 1st variable.

    Step 3: Finally, use your answer from Step 2 and substitute into Step 1 to solve for the 2nd variable.

    After you fix your typo, I can be more specific.
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  3. #3
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    sorry i was in a rush,
    here is the equation
    Solve using system of equations, with subsitution, check your answer when your done
    7x+4y=-2
    10x-3y=32
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  4. #4
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    Quote Originally Posted by mcinnes View Post
    sorry i was in a rush,
    here is the equation
    Solve using system of equations, with subsitution, check your answer when your done
    7x+4y=-2
    10x-3y=32
    Solve the first equation for x or y. Let's choose y for no reason.

    7x+4y=-2

    4y=-7x-2

    y=-\frac{7}{4}x-\frac{1}{2}

    Now substitute this back into the second equation.

    10x-3\left(-\frac{7}{4}x-\frac{1}{2}\right)=32

    10x+\frac{21}{4}x+\frac{3}{2}=32

    40x+21x+6=128

    61x=122

    x=\frac{122}{61}

    x=2

    Now plug this value into either equation you started with to find y.
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