Решите уравнение ; б) (4/5-х)+13/20=25/30
в) y-5/20=5/8-3/10
г) 2/3-(7/9-a)=1/3
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б) (4/5 - х) + 13/20 = 25/30

-х = - 4/5 - 13/20 + 25/30

х = 4/5 + 13/20 - 25/30

х = 48/60 + 39/60 - 50/60

х = 37/60

в) у - 5/20 = 5/8 - 3/10

у = 5/20 + 5/8 - 3/10

у = 10/40 + 25/40 - 12/40

у = 23/40

г) 2/3 - (7/9 - а) = 1/3

2/3 -7/9 + а = 1/3

а = 7/9 - 2/3 + 1/3

а = 7/9 - 3/9

а = 4/9