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  1. #1
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    couple problems math help

    Solve each system by the substitution method .Indicate whether each system is independent, inconsistent, or dependent.

    1) 3y=x+5
    2x-2y= -10



    2) x=1/8y-1
    y= 1/4x+39
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  2. #2
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    Quote Originally Posted by fancyface View Post
    1) 3y=x+5
    2x-2y= -10
    In first equation we have,
    x=3y-5
    Substitute,
    2(3y-5)-2y=-10
    6y-10-2y=-10
    4y=0
    y=0
    x=-5

    There is a unique solution.
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  3. #3
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    Quote Originally Posted by fancyface View Post
    Solve each system by the substitution method. ...
    2) x=1/8y-1
    y= 1/4x+39
    Hello,

    you have x=\frac{1}{8}y-1. Substitute the x in the 2nd equation:

    y=\frac{1}{4} \cdot \left( \frac{1}{8}y-1 \right) +39. Expand the RHS of this equation:

    y=\frac{1}{32}y-\frac{1}{4} +39. This will give:

    \frac{31}{32}y=\frac{155}{4}. Solve for y. I've got y = 40. Re-substitute this value in equation#1. I got x = 4.

    There is only this solution.

    EB
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