Question

Calcula :
$x {}^{2} + \frac{1}{x {}^{2} }$
$si \: x + \frac{1}{x} = 9$



​

Answer 1

Respuesta:

79

Explicación paso a paso:

$(x+\frac{1}{x} )^{2} = 9^{2} \\\\x^{2} + 2x\frac{1}{x} + \frac{1}{x^{2} } = 81\\\\x^{2} + 2 + \frac{1}{x^{2} }= 81\\\\x^{2} + \frac{1}{x^{2} }= 79$