1.m^2+3m+2=0时 为实数,解得m=-1或者m=-2
2.m^2+3m+2不等于0时为虚数,解得m不等于－1且不等于－2
3.m^2-4=0且m^2+3m+2不等于0时为虚数,解得m=2
4.m^2-4=0且m^2+3m+2=0时为0,解得m=-2