1.x/x+1-1=3/（x+1)(x-2) 两边乘以(x+1)(x-2)得x(x-2)-(x+1)(x-2)=3x²-2x-x²+x+2=3-x=1x=-1检验：x=-1是增根2.3/x+2+1/x=4/x²+2x 两边乘以x(x+2)得3x+x+2=44x=2x=1/2检验：x=1/2是方程的根3.2/3+x/3x...