(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
(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