х +4/15 = 2/3+ 2/5( 4/5 - х ) +13/20 = 25/30 у - 5/20 = 5/8 - 3/10 2/3 - (7/9 - а) =1/3. Created by настюлёк. matematika-ru

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nadin4 Х + 4/15 = 2/3 + 2/5
х + 4/15 = 10/15 + 6/15
х + 4/15 = 16/15
х = 16/15 - 4/15
х = 12/15 = 4/5
4/5 + 4/15 = 2/3 + 2/5
12/15 + 4/15 = 10/15 + 6/15
16/15 = 16/15
Ответ : х = 4/5

(4/5 - х) + 13/20 = 25/30
4/5 - х = 25/30 - 13/20
4/5 - х = 50/60 - 39/60
4/5 - х = 11/60
х = 4/5 - 11/60
х = 48/60 - 11/60
х = 37/60
(4/5 - 37/60) + 13/20 = 25/30
(48/60 - 37/60) + 13/20 = 25/30
11/60 + 13/20 = 25/30
11/60 + 39/20 = 25/30
50/60 = 25/30
25/30 = 25/30
5/6 = 5/6
Ответ: х = 37/60

у - 5/20 = 5/8 - 3/10
у - 5/20 = 25/40 - 12/40
у - 5/20 = 13/40
у = 13/40 + 5/20
у = 13/40 + 10/40
у = 23/40
23/40 - 5/20 = 5/8 - 3/10
23/40 - 10/40 = 25/40 - 12/40
13/40 = 13/40
Ответ: у = 23/40

2/3 - (7/9 - а) = 1/3
7/9 - а = 2/3 - 1/3
7/9 - а = 1/3
а = 7/9 - 1/3
а = 7/9 - 3/9
а = 4/9
2/3 - (7/9 - 4/9) = 1/3
2/3 - 3/9 = 1/3
6/9 - 3/9 = 1/3
3/9 - 1/3
1/3 = 1/3
Ответ: а = 4/9

1 votes Thanks 2

fanta2310

Verified answer

Х=2/3+2/5-4/15
х=12/15+4/15=16/15

(4/5-х)=25/30-13/20=500-390/600=110/600=11/60
х=4/5-11/60=48-11/60=37/60

у=5/8-3/10+5/20
у=23/40

(7/9-а)=2/3-1/3
(7/9-а)=1/3
а=7/9-1/3
а=7-3/9=4/9

2 votes Thanks 4

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