Выражение 1) 9/11b + 4/11c + 6/11c + 5/11b= 2) 11/13d - (8/13d + 4)= 3) 9/10n - (8/10n - 8)= / - дроби

1) 9/11b + 4/11c + 6/11c + 5/11b=14/11b+10/11c=1 3/11b+10/11c                                          2) 11/13d - (8/13d + 4)= 11/13d  -8/13d-4=3/13d-4
3) 9/10n - (8/10n - 8)=9/10n-8/10n+8=1/10n=8