1) 0.9-0.6(х-3)=2(0.2х-1.3)
2) -0.4(3х-1)+8(0.8х-0.3)=5-(3.8х+4)
3) 4/7(0.56-4.2у)+0.4=5/13(0.52-6.5у)

1)0.9-0.6х+1.8=0.4х-2.6 -0.6х-0.4х=-2.6-0.9-1.8-х=-5.3 /•(-1)х=5.32)-1.2х+0.4+6.4х-2.4=19х+20-1.2х+6.4х-19х=20-0.4+2.45.2х=22х=4.23)4/3.92-29.4у+0.4=5/6.76-84.5у29.4у+84.5у=0.7-1-0.4113.9у=-0.7у=0.006