Раскройте скобки и УПРОСТИТЕ уравнение. ДАЮ 50 БАЛЛОВ. 2/7 (1.4a-3 1/2 b)-1.2 (5/6a-0.5b)...

2/7 (1.4a-3 1/2 b)-1.2 (5/6a-0.5b)=2/7*(7а/5-7в/2)-6/5*(5а/6-в/2)=2*7а/(7*5)-2*7в/(7*2)-6*5а/(5*6)+6в/(2*5)=2а/5-в-а+3в/5=-0.4в-0,6а

1) 1,4a=14a/10=7a/5
2) 3 1/2b=7b/2
3) 2/7*(7a/5-7b/2)= $\frac{2*7a}{7*2}$ - $\frac{2*7b}{7*2}$ = $\frac{2a}{5}$ =2a/5-b
4) 1.2 (5/6a-0.5b)=12/10*(5a/6-5b/10)=6/5*(5a/6- b/2)= $\frac{6*5a}{6*5}$ - $\frac{6b}{2*5}$ =a-3b/5
5) 2a/5-b-(a-3b/5)=2a/5-b-a+3b/5=a(2/5-1)-b(1-3/5)=-3a/5-2b/5=-0.6a-0.4b