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  1. MHB Apprentice

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    #1
    Find x and y if x, y are members of real numbers and: (x+i)(3-iy)=1+13i

    I first expanded it to give: 3x-yix+3i+y=1+13i
    Then I equaled 3x+y=1 and -yx+3=13
    But afterwards I do other steps and get the wrong answer.
    Last edited by MarkFL; January 9th, 2017 at 22:10. Reason: Include Problem In Post

  2. Perseverance
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    #2
    Your approach and posted work are ok.

    To continue,

    $$3x+y=1\implies y=1-3x$$

    $$3-xy=13\implies xy=-10$$

    $$x(1-3x)=-10$$

    $$(3x+5)(x-2)=0$$

    $$(x,y)=\left(-\frac53,6\right),(2,-5)$$

    Does that match your results?

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