Question 200165
{xy = 20
2x^2 - y^2 + 4 = 0 
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y = 20/x
2x^2 - 400/x^2 + 4 = 0
x^4 + 2x^2 -200 = 0
*[invoke solve_quadratic_equation 1,2,-200]
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x^2 = -1 ± sqrt(201)
For the real number solutions:
x^2 = ~ 13.17745
x = ± 3.63
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Complex solutions:
x = ± sqrt(-15.17745)
x = ± 3.90i