[tex]x\to nr. \ de \ carti \\\\ \frac{2}{3} \ din \ x= \frac{2}{3}* x\to \frac{2x}{3}- a \ aranjat \\\\ x^{(3}-\frac{2x}{3}= \frac{3x-2x}{3}\to \frac{x}{3}-restul \\\\ \frac{x}{3}=30 \\\\ x=30*3 \\\\ \boxed{x=90 \ carti} \\\\ \hbox{Verificare:}\\\\\frac{2x}{3}+30=90 \\\\ \frac{2x}{3}=90-30 \\\\ \frac{2x}{3}=60 \\\\ x=\frac{3*\not60}{\not2} \\\\ x=3*30 \\\\ \boxed{x=90}[/tex]
