(х+27)-12=42

х+27=42+12

х+27=54

х=54-27

х=27

115-(15+у)=39

15+у=115-39

15+у=76

у=76-15

у=61

Verified answer

(х+27)-12=42

х+27=42+12

х+27=54

х=54-27

х=27

115-(15+у)=39

15+у=115-39

15+у=76

х=76-15

х=61