Scriem ca fractii ordinare
(3/9) la X+(3/9) la X+1 +(3/9) la X+2=
(1/3) la x + ( 1/3) la X+1 + (1/3) la X+2=
Scoatem factor comun 1/3 la puterea X1/
(1/3) la puterea X pe langa ( 1+1/3+1/9)=13/81
Aduci la acelasi numitor
1/3 la x pe langa (9+3+1 /9)=13/81
13/3la X*3la a doua=13/81
13/3la x+2=13/3 la a patra rezulta x+2=4
x=2
