几道一元一次方程,1.3x+1/5-x-5/2=1 2.1/2(x-3)-1/3(x-2)=5x/63.-6/5x-3=3/4 4.2x+1/3-10x+1/6=15.x-1/2[x-1/2(x-1)]=2/3(x-1)