а) 7/30 + x = 11/30
x = 11/30 - 7/30
x = 4/30 = 2/15
б) y + 1/13 = 6/13
y = 6/13 - 1/13
y = 5/13
в) z - 4/25 = 10/25
z = 10/25 + 4/25
z = 14/25
г) 18/40 - t = 9/40
- t = 9/40 - 18/40
- t = - 9/40
t = 9/40
а) 7/30 + x = 11/30
x = 11/30 - 7/30
x = 4/30 = 2/15
б) y + 1/13 = 6/13
y = 6/13 - 1/13
y = 5/13
в) z - 4/25 = 10/25
z = 10/25 + 4/25
z = 14/25
г) 18/40 - t = 9/40
- t = 9/40 - 18/40
- t = - 9/40
t = 9/40