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Math Help - Equation system

  1. #1
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    Equation system

    Solve the following system of equation for x,y\in\mathbb{R}:
    x^3+4y=y^3+16x
    \frac {1+y^2}{1+x^2}=5
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  2. #2
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    Quote Originally Posted by james_bond View Post
    Solve the following system of equation for x,y\in\mathbb{R}:
    x^3+4y=y^3+16x
    \frac {1+y^2}{1+x^2}=5
    x^3-16x = y^3-4y

    x(x^2-16) = y(y^2-4)<br />

    \frac {1+y^2}{1+x^2}=5

    1+y^2 = 5+5x^2

    y^2 = 4+5x^2


    x(x^2-16) = y(5x^2)

    y = \frac{x^2-16}{5x}


    \frac{(x^2-16)^2}{25x^2} = 4 + 5x^2

    x^4 - 32x^2 + 256 = 100x^2 + 125x^4

    0 = 124x^4 + 132x^2 - 256

    0 = 31x^4 + 33x^2 - 64

    0 = (x^2-1)(31x^2 + 64)

    0 = (x-1)(x+1)(31x^2+64)

    can you finish?
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