Question

se (x^-1 + y^-1)^-1 = 2 , então y vale:

Answer 1

Resposta:

$y=\frac{2x}{x-2}$

Explicação passo-a-passo:

$(x^{-1} + y^{-1})^{-1} = 2\\\\\frac{1}{(x^{-1} + y^{-1})} = 2 \\\\\frac{1}{\frac{1}{x} +\frac{1}{y}} = 2 \\\\2\ {\cdot}\ (\frac{1}{x} +\frac{1}{y})=1\\\\\frac{2}{x} +\frac{2}{y}=1\\\\2y+2x=xy\\\\2x=xy-2y\\\\2x=y(x-2)\\\\y=\frac{2x}{x-2}$