Question

Exercițiul 27) subpunctul b, va rog!

Answer 1

x+ 1/x =3; ridicam la puterea a 3-a

(x+ 1/x)³=3³

x³+3•x²/x+3•x/x²+1/x³=27

x³+3(x+1/x)+1/x³=27

x³+3•3+1/x³=27

x³+1/x³=27-9

x³+1/x³=18