Question

x la puterea a3a + 1 supra x la puterea a3a

Answer 1

$Este: x^{3} + \frac{1}{ x^{3}} sau \frac{ x^{3}+1 }{ x^{3}} ???$

Ai ales prima varianta si ai spus ca 

$x^{3} + \frac{1}{ x^{3} } = 4$

Aducem la acelasi numitor:

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

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

Answer 2

(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