[tex]\dfrac{3x+3y}{36}=\dfrac{3(x+y)}{36}=\dfrac{x+y}{12}\\
\text{O fractie este echiunitara daca si numai daca numaratorul este egal cu}\\ \text{numitorul.}\\
x+y=12;\ x\neq 0\\
(x,y)\in \{(3,9);(4,8);(5,7);(6,6);(7,5);(8,4);(9,3)\}\\
S:\overline{xy}\in \{39,48,57,66,75,84,93\}[/tex]
