927-349=627+x
627+х=578
х=578-627
х=-49
Проверка
927-(627-49)=349
927-578=349
349=349
927-627-х=349;
927-627-349=х;
х= -49
927-349=627+x
627+х=578
х=578-627
х=-49
Проверка
927-(627-49)=349
927-578=349
349=349
927-627-х=349;
927-627-349=х;
х= -49