Question

方程x/x-1 -1=m/(x-1)(x+2)有增根,则m的值为 A 0和3 B 1 C 1和-2 D 3

Answer 1

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