3)a) 3(y-5)-2(y-4)=3y-15-2y+8=y-7;
б)-5(5-х)-4х=-25+5х-4х=х-25;
в)1/3 *3х-1/3 *(-6) -2/7 *7х +2/7 *21=х+2-2х+6=8-х;
г)5,4(3y-2) -7,2(2y-3)=13,2y -10,8-14,4y+21,6=10,8-1,2y
д)=(2*1,8m)/9 -(25,4)/9 - (3*2,1m)/7 +(3*4,2)/7=04m-1,2-0,9m+1.8=0,6-0,5m
е)=0,1y-0,2-0,1y+0,2=0