Hin Pand asked in 科學及數學數學 · 1 decade ago

二元一次方程

二元一次方程

X÷3+Y÷5=2

X÷5+Y÷3=-2

請例式

1 Answer

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  • 1 decade ago
    Best Answer

    X÷3+Y÷5=2

    X÷5+Y÷3=-2

    2條都乘15, 變成

    5x + 3y = 30

    3x + 5y= -30

    5同3的lcm係15

    上面eqn 乘3

    下面eqn乘5

    15x + 9y= 90

    15x + 25y = -150

    上面eqn減下面eqn

    -16y = 240

    y = -15

    代入 X÷3+Y÷5=2

    x/3 + (-15/5) = 2

    x/3-3 = 2

    x/3 = 5

    x = 15

    Source(s): maths tutor
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