Question

упростите выражение 2/7*(1,4а - 3 1/2b)-1,2(5/6а-0,5b)

Answer 1

2/7(1,4a-3 1/2 b)=2/7(7/5a-7/2b)=2/5a-b 
1.2(5/6а-0.5b)=6/5(5/6a-5/10b)=a-3/5b 
2/5a-b-a+3/5b=-3/5a-2/5b=-0.6a-0.4b