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