Question

若直线x+(1+m)y+(m-2)=0与直线mx+2y+6=0重合,m=?

Answer 1

m不等于-1时

1/(1+m)=m/2

(1+m)m=2

m^2+m-2=0

m=1,m=-2

m=1时,不满足重合条件

m=-2时,也不满足

m=-1时,也不满足

应该是空集