Задание 2/9+x=7/9 6/11-x=4/11 x-3/7=2/7 4/15+6/15= 27/28-25/28=
2/9+х=7/9 х=7/9-2/9 х=5/9
6/11-х=4/11
х=6/11-4/11
х=2/11
х-3/7=2/7
х=3/7+2/7
х=5/7
4/15+6/15
=10/15=2/3
27/28-25/28=2/28+1/14
2/28=1/14*