题目内容
试题答案
A.A1A2+B1B2=0 B.A1A2-B1B2=0 C.=-1 D.=1
两条直线A1x+B1y+C1=0与A2x+B2y+C2=0垂直的充要条件是
A1A2+B1B2=0
A1A2-B1B2=0
=-1
=1