Quantitative Reasoning

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  • PE1.11
  • #29676

    Ezra Halleck
    Participant

    11. Solve
    x – 3y = 6
    4x + 3y = 9
    using the substitution method

    #29786

    BriannaC
    Participant

    X-3y=6
    4x+3y=9 Plug in y=1 into the original equation.
    X-3(-1)=6
    X+3=6
    -3=-3
    X=3
    Multiply -4 to the first equation.
    -4x+12y=-24
    4x+3y=9. Y=1. X=3
    __________
    15y=-15/15
    Y=1

    #29787

    Rackesh
    Participant

    x – 3y = 6
    4x + 3y = 9

    X= 3y+6

    4(3y+6) +3y = 9

    12y+24 + 3y = 9

    15y + 24 = 9

    15y = -15

    y= -1

    X= 3(-1)+6

    X = 3

    {3,-1}

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