200×(х+71)=54000;900×(16-с)=5400; 400×(х-12)=3600;
200×(x+71) =54000 900×(16-c)=54000 400×(x-12)=36000 x= 54000÷200-71 c= 54000÷900-16 x= 36000÷400+12 x=199 c= 44 x=102