4.2*(0.8+у)=8.82 3.36+4.2у=8.82 4.2у=8.82-3.36 4.2у=5.46 у=5.46:4.2 у=1.3 ОТВЕТ: 1.3 0.2t+1.7t-0.54=0.22 1.9t=0.22+0.54 1.9t=0.76 t=0.76:1.9 t=0.4 ОТВЕТ: 0.4