упрастите а)5*(x-2)-6*(x+3)-4*(2x-9)
б)4/9*(2,7y-2 1/4x)-4,2*(5/4y-0.5x)

а) 5*(х-2)-6*(х+3)-4*(2х-9)5х-10-6х-18-8х+36-9х=-8х=8/9б) 4/9*(2,7у-2 1/4х)-4,2*(5/4у-0,5х)54/45у-1х-21/4у+21/10х54/45у-21/4у=216/180у-945/180у=-729/180у=-4,05у21/10х-1/1х=21-10/10х=11/10х=1,1хОтвет: 1,1х-4,05у