2.5x-1.8+0.5x=0.6 15.6-2(x-7.4)=12.4 0.86*2-7.1x=0.3 35-x=4(x+5) 解方程

x=0.8，x=9，x=0.2，x=3

2.5x-1.8+0.5x=0.63x=0.6+1.8x=0.815.6-2(x-7.4)=12.415.6-2x+2*7.4=12.4-2x=12.4-15.6-2*7.4-2x=-18x=90.86*2-7.1x=0.3-7.1x=0.3-1.72(0.86*2的积)-7.1x=-1.42x=0.235-x=4(x+5)35-x=4x+4*535-20=4x+x5x=15x=3