[m](13\frac{4}{53}-x)=14-\frac{76}{53}[/m]
[m]\frac{13\cdot 53+4}{53}-x=\frac{14\cdot 53}{53}-\frac{76}{53}[/m]
[m]\frac{693}{53}-x=\frac{742-76}{53}[/m]
[m]x=\frac{693-666}{53}[/m]
[red][m]x=\frac{27}{53}[/m][/red]
Проверка:
[m]14-(13\frac{4}{53}[/m]-[red][m]\frac{27}{53}[/m][/red])=[m]\frac{76}{53}[/m]
[m]14-(\frac{693}{53}[/m]-[red][m]\frac{27}{53}[/m][/red])=[m]\frac{76}{53}[/m]
[m]14-[/m][red][m]\frac{693-27}{53}[/m][/red]=[m]\frac{76}{53}[/m]
[m]\frac{742-666}{53}=\frac{76}{53}[/m]- верно