6,7y+13+3,1y=86,5 2,8+K+3,7=12,5 (5,6-y)+3,8=4,4
6.7у+13+3.1у=86.5 6.7у+3.1у=86.5-13 9.8у=73.5 у=73.5:9.8 у=7.5 2.8+к+3.7=12.5 к=12.5-2.8-3.7 к=6 (5.6-у)+3.8=4.4 5.6-у=4.4-3.8 5.6-у=0.6 у=5.6-0.6 у=5
6.7y+3.1y=86.5-13 9.8y=73.5 y=7.5 k=12.5-2.8-3.7 k=6 5.6-y+3.8=4.4 -y=4.4-5.6-3.8 -y=-5 y=5