(x+27)-12=42,
Х+27=54
Х=27
115-(35+y)=39,
-35-у=39-115
-35-у=-76
35+у=76
У=76-35
У=41
z-35-64=16,
z-99=16
z=16+99
z=115
28-t+35=53
63-t=53
-t=53-63
-t=-10
t=10