35+23+Х=100. (30-15)+У=80. Х-(23+17)=60. а+(45-30)=75. 70-а=8+9+2. х+12=50-(15+5)

1) 35+23+х=100 58+х=100 х=100-58 х=42 2) (30-15)+у=80 15+у=80 у=65 3) х-(23+17)=60 х-23-17=60 х-40=60 х=60+40=100 4)