Ответ:
1)
a)5,6 + (11 + 7,4)=5,6+18,4=24
б)4,3 + (3,7 – 8)=4,3+(-4,3)=0
в)3 1/9 - (3,5 + 2 1/9)=28/9-(7/2+19/9)=28/9-101/18=-5/2
г)7 5/14-(3 2/13-8 9/14)=103/14-(41/13-121/14)=103/14-(-999/182)=103/14+999/182=167/13
2)
a)3*a*1,8=5,4a
б)a*(12,5)*4=a*50=50a
в)-7*a(-1 3/7)*b=-7*a(-10/7)*b=a*10b=10ab
3)
a)8m-3m=(8-3)m=5m
б)5n+7n-n=5n+7n-1n=(5+7-1)n=11n