x/(x-1) -1=m/(x-1)(x+2)
x(x+2)-(x-1)(x+2)=m
x²+2x-(x²+x-2)=m
x²+2x-x²-x+2=m
x+2=m
方程有增根,说明x=1或-2
所以当x=1时,m=3
当x=-2时,m=0
所以选 A 0和3