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Se stie ca a+1supra a=4.Aflati a la2 +1 supra a la 2

Răspuns :

[tex] a+\frac{1}{a}=4 [/tex] .Ridicam la patrat, si obtinem: [tex] a^{2}+2*a* \frac{1}{a}+ \frac{1}{ a^{2} }=16 <=> a^{2}+ \frac{1}{a^{2}}+2=16 => a^{2}+ \frac{1}{ a^{2} } =14. [/tex]
x:x+1:x=4
[tex] \frac{1+1}{x} [/tex]=4
[tex] \frac{1}{3} [/tex]=x