1) 9(5х-10)-12(х-4)=45х-90-12х+48=33х-42
2) -4(5х-4)-10(2х+4)=-20х+16-20х-40=-40х-24
3) 6(3у-4)-2(9у-11)+2=18y-24-18y+22+2=0
4) 8(2у-5)-4(3у-10)=16y-40-12y+40=4y
5) 2(а-4)-(1-2а)=2a-8-1+2a=4a-9
6) (4a-b)-5a+3b=4a-b-5a+3b=-a+2b
7) -(3x-0.4)+(0.4x-3)=-3x+0.4+0.4x-3=-2.6x-2.6