1) 1 3/7 - х = 4/7
-х = 4/7 - 1 3/7
-х = 4/7 - 10/7
-х = -6/7
х = 6/7
2) 2 17/20 + (у - 1 5/20) = 5 11/20
2 17/20 + у - 1 5/20 = 5 11/20
у = 5 11/20 - 2 17/20 + 1 5/20
у = (111/20-57/20) + 1 5/20
у = 27/10 + 1 5/20
у = 2 7/10 + 1 5/20
y = 27/10 + 25/20
y = 54/20 + 25/20
y = 79/20
y = 3 19/20
