[tex]\displaystyle\bf\\fie~a~numarul.\\2\bigg (a-\frac{1}{3}933 +300\bigg)=978 \Leftrightarrow 2\bigg(a-311+300\bigg)=978 \Leftrightarrow 2\bigg(a-11\bigg)=978,\\a-11=\frac{1}{2}978 \Leftrightarrow a-11=489 \Leftrightarrow a=489+11 \implies a=500.[/tex]
