Решите уравнения двумя способами,(х+27)-12=42 ,115-(35+у)=39
(х+27)-12=42 (х+27)-12=42 x-27-12=42 x-27-12=42 x=42+27+12 x-39=42 x=81 x=42+39 x=81 115-(35+у)=39 115-(35+у)=39 115-35-y=39 115-35-y=39 -y=39-115+35 80-y=39 -y=-41 -y=39-80 y=-41:(-1) -y=-41 y=41 y=-41:(-1) y=41