A) x+27 - 12=42 x+15=42 x=42-15 x= 27 б) 115 - 35 -y =39 80-y=39 y=80-39 y=41 в) z-35-64=16 z=35+64+16 z=115 г) 28-t+35 = 53 t=28+35-53 t=10