(3 1/7-n)+1 4/7=3 5/7+2/7
(3 1/7-n)+1 4/7=3 7/7
(3 1/7-n)=3 7/7-1 4/7
(3 1/7-n)=2 3/7
-п=3 1/7-2 3/7
-п=2 8/7-2 3/7
-п=5/7
п=-5/7
(31/7-n)+14/7=3 7/7 (3 1/7-n)= 3 7/7-1 4/7 (3 1/7-n)=2 3/7 -n=3 1/7-2 3/7 -n=2 8/7-2 3/7 -n=5/7 n-5/7