5 10/11-(5/11+1/11)=5 10/11-6/11=5 4/11
3-(7/15-1/15)=3-6/15=2 15/15-6/15=2 9/15=2 3/5
1-(3/10+3/10)=1-6/10=10/10-6/10=4/10=2/5
4-(2/9+4/9)=4-6/9=3 9/9-6/9=3 3/9=3 1/3
A+|a-4|=a-(a-4)=4.........................
Сороки: 2х,
синицы: х,
снегири: 3х
2х+х+3х=18
6х=18
х=18/6
х=3