1/2x=2/(x+3)
x+3=4x
3x=3
x=1
x/(x+1)=2x/(3x+3）+1
3x=2x+3x+3
2x=-3
x=-3/2
2/(x-1)=4/(x^2-1)
2/(x-1)=4/(x+1)(x-1)
2x+2=4
x=1(增根,无解）
5/（x^2+x)-1/(x^2-x)=0
5/[x(x+1)]-1/[x(x-1)]=0
5x-5-x-1=0
4x=6
x=3/2
x/(x-3)=(x+1)/(x-1)
x^2-x=x^2-2x-3
x=-3
以上分式需要检验,这里省略