(х+27)-12=42
х+27=42+12
х+27=54
х=54-27
х=27
х+27-12=42
х+15=42
х=42-15
115-(35+у)=39
-(35+у)=39-115
-(35+у)=-76
-35-у=-76
-у=-76+35
-у=-41
х=41
115-35-у=39
80-у=39
-у=39-80
у=41
(х+27)-12=42
(х+27)-12=42
х+27=42+12
х+27=54
х=54-27
х=27
(х+27)-12=42
х+27-12=42
х+15=42
х=42-15
х=27
115-(35+у)=39
115-(35+у)=39
-(35+у)=39-115
-(35+у)=-76
-35-у=-76
-у=-76+35
-у=-41
х=41
115-(35+у)=39
115-35-у=39
80-у=39
-у=39-80
-у=-41
у=41