1. 8х-56-6х-27=15 2х=98 х=49 2. 0.15у-0.6=9.9-0.3у+0.3 0.45у=10.8 у=24 3. 0.6 -0.5х+0.5=х+0.5 1.5у=0.6 у=0.4 4. у-0.5-0.5+у+1=0 2у-1+1=0 2у=0 у=0