540:(17-х)=60
17-х=540:60
17-х=9
х=17-9
х=8
проверка
540:(17-8)=60
540:9=60
60=60
t*7-80=340
t*7=340+80
t*7=420
t=420:7
t=60
60*7-80=340
420-80=340
340=340
(8*у-30):9=50
8*у-30=50*9
8*у-30=450
8*у=450+30
8*у=480
у=480:8
у=60
(8*60-30):9=50
(480-30):9=50
450:9=50
50=50
(350:b+10)*7=560
350:b+10=560:7
350:b=80-10
350:b=70
b=350:70
b=5
(350:5+10)*7=560
(70+10)*7=560
80*7=560
560=560
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(это проверка)
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540:(17-х)=60
17-х=540:60
17-х=9
х=17-9
х=8
проверка
540:(17-8)=60
540:9=60
60=60
t*7-80=340
t*7=340+80
t*7=420
t=420:7
t=60
проверка
60*7-80=340
420-80=340
340=340
(8*у-30):9=50
8*у-30=50*9
8*у-30=450
8*у=450+30
8*у=480
у=480:8
у=60
проверка
(8*60-30):9=50
(480-30):9=50
450:9=50
50=50
(350:b+10)*7=560
350:b+10=560:7
350:b=80-10
350:b=70
b=350:70
b=5
проверка
(350:5+10)*7=560
(70+10)*7=560
80*7=560
560=560
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(это проверка)
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