(4х-у)-(2х+у)
х-(4+3х-х)+(2-х)
5+(2х-х)-(4х+5)+х
3а(а+3а-2)
5х(2-3х)+3(5х-х)-7(х-1)
5х+15х-25х

(4х-у)-(2х+у)=2х-2у

 х-(4+3х-х)+(2-х) = -2х -45+(2х-х)-(4х+5)+х= -х3а(а+3а-2)=3а²+9а²-6а=12а²-6а=6(2а²-а) 5х(2-3х)+3(5х-х)-7(х-1)=10х-15х²+15х-3х-7х+7=15х²+15х+7 5х+15х-25х = -5х