Verified answer

1. х+(1200-900)=1500

х+300=1500

х=1500-300

х=1200

Ответ:х=1200

2.(50*30):у=15

1500:у=15

у=1500:15

у=100

Ответ:у=100

3.с:(1200:2)=3

с:600=3

с=600*3

с=1800

Ответ:с=1800

Verified answer

х+(1200-900)=1500

х+300=1500

х=1500-300

х=1200

(50*30):у=15

1500:у=15

у=1500:15

у=100

с:(1200:2)=3

с:600=3

с=3*600

с=1800