Question

若直線ax+y-1=0與直線4x+(a-3)y-2=0垂直，則實數a的值等于(    )

A.-1              B.4                  C.                  D.-

Answer 1

C

解析：k₁=-a,k₂=.∴兩直線垂直,則k₁·k₂=-1,即=1a=.故選C.