1)1.5*(х-2у)-4*(5х+2у)+2.5х=1.5x-3y-20x-8y+2.5x=1.5x+2.5x-20x-11y=-16x-11y
2)1.4*(2х-у)-2*(5х-2у)+1.5у=2.8x-1.4y-10x+4y+1.5y=-7.2x+0.1y
3)12-(2х-у)-2*(5х-2)+3.3у=12-2x+y-10x+4+3.3y=16+4.3y-12x
4)3*(2-3у)-2*(5х-у)-0.7у-2.3 =6-9y-10x+2y-0.7y-2.3=3.7-10x-7.7y