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x la puterea a3a + 1 supra x la puterea a3a

Răspuns :

[tex]Este: x^{3} + \frac{1}{ x^{3}} sau \frac{ x^{3}+1 }{ x^{3}} ???[/tex]

Ai ales prima varianta si ai spus ca 

[tex] x^{3} + \frac{1}{ x^{3} } = 4[/tex]

Aducem la acelasi numitor:

x³ + 1 = 4x³
4x³ - x³ = 1
3x³ = 1
x³ = 1/3

[tex]x = \sqrt[3]{ \frac{1}{3} } = \frac{1}{ \sqrt[3]{3} } = \frac{ \sqrt[3]{ 3^{2} } }{3} = \frac{ \sqrt[3]{9} }{3} [/tex]

(x+1)/x=4  <=>   x/x  +1/x =4

x/x + 1/x=4

1+1/x=4

1/x=4-1

1/x=3

x=3

x³ +  1/x³=  3³ + 1/3³=  27  + 1/27     aducem la acelasi numitor

(729+1)/27=   730/27