х:20 = 180:9
х:20 = 20
х=20*20
х=400
100 + X:20 = 240
х:20 = 240 -100
х:20 = 140
х=140*20
х=2800
60 + 360 : х = 100
360 : х = 100 -60
360 : х = 40
х=360:40
х= 9
х:20 = 180:9
х:20 = 20
х=20*20
х=400
100 + X:20 = 240
х:20 = 240 -100
х:20 = 140
х=140*20
х=2800
60 + 360 : х = 100
360 : х = 100 -60
360 : х = 40
х=360:40
х= 9
x:20=20
x=20•20
x=400