(200-x)-98=75
200-x= 75+98
200-х=173
-х=173-200
х=27
(200-х)-98=75
200-х=75+98
х=200-173
х=27 проверка
(200-27)-98=75
(300+х)+200=800
300+х=800-200
300+х=600
х=600-300 х=300
