3,6 + 4,8 * (8 3/4 - 7 5/6) = 36/10 + 48/10 * (35/4 - 47/6) = 36/10 + 48/10 * ((105-94)/12) = 36/10 +48/10 * 11/12 = 36/10 + 44/10 = 80/10 = 8
1)2/3:5/6=4/5
2)5/9-4/5=25/45-36/45=-11/45
3)-11/45+2/3=-11/45+30/45=19/45
4)19/45-1/2=38/90-45/90=-7/90
5)-7/90-2/9=-7/90-20/90=-27/90=-3/10
А:b+c*(a-b)=84:14+3*(84-14)=216