algebra 1

Solve each linear system by substitution method.

x+2y=7
2x+4y=8

I'm getting stuck. Could some one explain the work out process and what the outcome means?

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  1. change the first to x = 7 - 2y
    sub that into the second

    2x + 4y = 8
    2(7-2y) + 4y = 8
    14 - 4y + 4y = 8
    14 = 8 ???? Wow

    When this happens there is no solution

    Looking at your equations more closely, ..
    divide the second by 2 to get
    x + 2y = 8 and the first said
    x + 2y = 7 ... contradiction !

    What you are looking at is really two straight lines that are parallel, they cannot intersect.

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