1) (x+1x)2$=x^2+2+\frac{1}{x^2}=9=>x+\frac{1}{x}=3(x>0)(x+1x)3=x^3+\frac{1}{x^3}+3.(x+\frac{1}{x})=27=>x^3+\frac{1}{x^3}=18nguyênđỏxxanh=x^5+\frac{1}{x^5}+(x+\frac{1}{x})nguyên=> đpcm$
1)
(x+1x)2$=x^2+\frac{1}{x^2}
$$+2=9=>x+\frac{1}{x}=3(x>0)
(x+1x)3=x^3+\frac{1}{x^3}
$$+3.(x+\frac{1}{x})=27=>x^3+\frac{1}{x^3}=18
nguyênđỏxxanh=x^5+\frac{1}{x^5}+(x+\frac{1}{x})
nguyên=> đpcm$