реши уравнение с проверкой : 200×(х+71)=5400; 900×16-900с=5400; 400×(х-12)=3600

1. 200×(x+71)=5400X+71=27X=27-71X=-442.900×16-900c=54014400-900c=540-900c=540-14400-900c=-13860C=15,43.400×(x-12)=3600X-12=9X=9+12X=21