А.xz+xy+2z+2y = ...x(z+y)+2(z+g)<span>
Б.2ab-2ac+3b-3c = ...2</span>a(b-c)+3(b-c)<span>
В.5ax+10ay+bx+2by = ...5</span>a(x+2y)+b(x+2y)<span>
Г.3ac+6bc+7ax+14 bx = ...3</span>c(a+2b)+7x(a+2b)<span>
Д.2ax+2xy-an-yn = ...2</span>x(a+y)-n(a+y<span>)</span>
(n+2)!(n^2-9)/(n+4)!= (n+2)!(n^2-9)/((n+2)!(n+3)(n+4))=(n^2-9)/((n+3)(n+4))=
=(n^2-9)/(n^2+7n+12)=(n^2+7n+12-7n-21)/(n^2+7n+12)=1 - (7n+21)/(n^2+7n+12)
<span>-8-2(1-b)-2b+1= -8-2-2b-2b+1= -10-4b+1= -9-4b
</span>a(b-c)+b(c-a)-c(b-a)=ab-ac+bc-ba