题目当B和D取何值时,直线 ) x-2y+z-9=0 3x+By+z+D=0 . 在xOy-|||-面上?-|||-bigcirc A. =6, D=-27-|||-bigcirc B. =-6, D=-27-|||-bigcirc C. =6, D=27-|||-bigcirc D. B=-6 =27题目解答答案