1.
х+7/12=3/4
х=3/4-7/12
х=9-7/12
х=2/12= 1/6
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1/6+7/12=3/4
2+7/12=3/4
9/12=3/4
3/4=3/4
2.
х-1/6=1/9
х=1/9+1/6
×=2+3/18
×=5/18
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5/18-1/6=1/9
5-3/18=1/9
2/18=1/9
1/9=1/9
3.
×-3/5=3/8
×=3/8+3/5
×=15+24/40
×=39/40
-----------------
39/40-3/5=3/8
39-24/40=3/8
15/40=3/8
3/8=3/8
4.
×+5/24=7/12
×=7/12-5/24
×=14-5/24
×=9/24=3/8
------------------
3/8+5/24=7/12
9+5/24=7/12
14/24=7/12
7/12=7/12
5.
у+2/7=1/3
у=1/3-2/7
у=7-6/21
у=1/21
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1/21+2/7=1/3
1+6/21=1/3
7/21=1/3
1/3=1/3
6.
×-1/6=7/9
×=7/9+1/6
×=14+3/18
×=17/18
-----------------
17/18-1/6=7/9
17-3/18=7/9
14/18=7/9
7/9=7/9