simultaneous equation

x^2+y^2-2xy=21
x^2+2xy-8y^2=0
find x and y
help me plz

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  1. x^2+2xy-8y^2=0
    (x+4y)(x-2y) = 0
    so two routes to follow

    x = 2 y and x = -4y

    now the first one with x = 2 y

    4 y^2 + y^2 - 4 y^2 = 21
    y = +21 or - 21
    then x = 42 or -42
    so
    (42,21) (-42,-21)

    now the first one with x = -4y
    I will leave that for you

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    posted by Damon
  2. f gwsertg wreg

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    posted by sdfg sd

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