平行不重合A1B2=A2B1且C1B2≠C2B1

相交：A1B2≠A2B1

垂直：B1B2≠0时,A1A2=-B1B2

B1=0,A2=0或B2=0,A1=0

重合：A1B2=A2B1且C1B2=C2B1