Question

$x - \frac{1}{x } = 3$
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Answer 1

$x(x-\frac{1}{x}=3)$

$x^2-1=3x$

$x^2-3x-1=0$

Aplicando a fórmula quadrática:

$x_{1,2}=\frac{-(-3)±\sqrt{(-3)^2-4(1)(-1)}}{2(1)}$

$x_{1,2}=\frac{3±\sqrt{13}}{2}$

$\mathbb{S}=\{\frac{3+\sqrt{13}}{2},\frac{3-\sqrt{13}}{2}\}$