Выражения 2/7(1,4a-3 1/2b)-1,2(5/6a-0,5b)

2/7(1,4a-3 1/2b)-1,2(5/6a-0,5b)=2/7*1,4a-2/7*3 1/2b-1.2*5/6a-1.2*(-0.5b)=
= 2/7*1 4/10a-2/7*7/2b-1 2/10*5/6a-1 2/10*(-5/10b)=
=2/7*14/10a-b-12/10*5/6a-12/10*(-5/10b)=2/5a-b-a+3/5b=
=2/5a-5/5b-5/5a+3/5b=-3/5a-2/5b