Пошаговое объяснение:

1)10.8/15-4.1/12=6.32/60-5/60=6. 27/60=6.9/20

2)6.9/20+5.7/20=11.16/20=11.4/5

2:

1)7-2.7/10= 4.10/10-7/10=4.3/10

2)2.5/6+4.3/10=6.25/30+9/30=6.34/30= 7.4/30=7.2/15

4.17/24-х=1.5/12

х=4.17/24-1.5/12=3.17/24-10/24=3.7/24

х=3.7/24

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4.17/24-3.7/24= 1.10/24=1.5/12

(х-5/6)+1.1/2=5.7/12

х-5/6=5.7/12-1.1/2=4.7/12-6/12=4.1/12

х=4.1/12+5/6= 4.11/12

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(4.11/12-5/6)+1.1/2=5.7/12