(х+27)-12=42 х+27=42+12 х+27=54 х=54-27 х=27 115-(35+у)=39 -35-у=39-115 -35-у=-76 -у=-76+35 -у=-41 у=41 z-35-64=16 z=16+35+64 z=115 28-t+35=53 -t=53-28-35 -t=-10 t=10