Hola,
Sea: x= el número
Entonces:
[tex]x+ 2\frac{1}{x} =3,5 \\ x^{2} -3,5x+2=0 \\ Sacamos la solucion con la formula general: x_{1,2} = \frac{-b+- \sqrt{ b^{2}-4ac } }{2a} \\ x_{1}= \frac{3,5+ \sqrt{ 3,5^{2}-4(1)(2) } }{2} \\ x_{1}= \frac{7+ \sqrt{ 17 } }{4} \\ x_{1}=2,78 \\ \\ x_{2}= \frac{3,5- \sqrt{ 3,5^{2}-4(1)(2) } }{2} \\ x_{2}= \frac{7- \sqrt{ 17 } }{4} \\ x_{2}=0,72[/tex]
