2/7(1,4a-3 1/2 b)=2/7(7/5a-7/2b)=2/5a-b
<span>1.2(5/6а-0.5b)=6/5(5/6a-5/10b)=a-3/5b </span>
<span>2/5a-b-a+3/5b=-3/5a-2/5b=-0.6a-0.4b</span>
<span>350*408*2-(168+156):2 =285438
1) 168+156=324
2)350*408=142800
3)142800*2=285600
4)324:2=162
5)285600-162=285438</span>