2 1/3x = 1/3-2/7
7/3х = 1/3 - 2/7
7/3х = 1/21
х = 1/49.
1/5+x= 3/4 : 9/12
1/5 + х = 3/4 × 12/9
1/5 + х = 3 × 3/9
1/5 + х = 1
х = 1 - 1/5
х= 4/5.
2 1/3x = 1/3-2/7
7/3х = 1/3 - 2/7
7/3х = 1/21
х = 1/49.
1/5+x= 3/4 : 9/12
1/5 + х = 3/4 × 12/9
1/5 + х = 3 × 3/9
1/5 + х = 1
х = 1 - 1/5
х= 4/5.