;(m²+m-2)x+(m²+3m+2)y-5=0若l与x轴平行
则
m^2+3m+2≠0 (m+2)(m+1)≠0 m≠-2 m≠-1
m^2+m-2=0 (m+2)(m-1)=0 m=-2或m=1
则综合
m=1