а) 3m+2m+4m=9m
б)1/2а+1/3а-1/6а=3/6а+2/6а-1/6а=4/6а=2/3а
в)0,9b-1,3b+0,7b=0,3b
г)x-0,2x-0,7x=0,1x
д)1/12m-1/4m-1/3m=1/12m-3/12m-4/12m=-6/12m=-1/2m=-0,5m
e)c-0,8c-1/5c-1/2c=c-0,8c-0,2c-0,5c=-0,5c
ж)0,3a-0,2b-0,7a+0,2b=-0,4a
з)4a-6a-2a+12-11=1-4a
и)2/3а+3/8b-1/6a-1/4b=4/6a+3/8b-1/6a-2/8b=3/6a+1/8b=1/2a+1/8b
к)5/7k-2/3-3/14k-1/3=10/14k-3/14k-2/3-1/3=7/14k-1=1/2k-1
л)0,2m-2/9-4m+5/9=3/9-3,8m=1/3-3,8m
м)1/2а+1/3с-1/2а+2/3с=1/3с+2/3с=1с=с