5) у + 2/7 = 1/3
у = 1/3 - 2/7
у = 1*7/3*7 - 2*3/7*3
у = 7/21 - 6/21
у = (7-6)/21
у = 1/21
Проверка:
1/21 + 2/7 = 1*1/21*1 + 2*3/7*3 = 1/21 + 6/21 = (1+6)/21 = 7/21 = 1*7/3*7 = 1/3
1/3 = 1/3
6) х - 1/6 = 7/9
х = 7/9 + 1/6
х = 7*2/9*2 + 1*3/6*3
х = 14 /18 + 3/18
х = (14+3)/18
х = 17/18
Проверка:
17/18 - 1/6 = 17*1/18*1 - 1*3/6*3 = 17/18 - 3/18 = (17-3)/18 = 14/18 = 7*2/9*2 = 7/9
7/9 = 7/9
7) у - 3/8 = 5/32
у = 5/32 + 3/8
у = 5*1/32*1 + 3*4/8*4
у = 5/32 + 12/32
у = (5+12)/32
у = 17/32
Проверка:
17/32 - 3/8 = 17*1/32*1 - 3*4/8*4 = 17/32 - 12/32 = (17-12)/32 = 5/32
5/32=5/32
8) у + 2/5 = 1/2
у = 1/2 - 2/5
у = 1*5/2*5 - 2*2/5*2
у = 5/10 - 4/10
у = (5-4)/10
у = 1/10
Проверка:
1/10 + 2/5 = 1*1/10*1 +2*2/5*2 = 1/10 + 4/10 = (1+4)/10 = 5/10 = 1/5/2*5 = 1/2
1/2 = 1/2