直线l1:ax+3y+1=0;x+(a-2)y+a=0,它们的倾斜角及斜率依次分别为a1,a2,k1,k2
直线l1:αx+3y+1=0;x+(α-2)y+α=0,它们的倾斜角及斜率依次分别为α1,α2,k1,k2.,
①α=( )时,a1=150°
②α=( )时,l2⊥x轴
③α=( )时,l1‖l2
④α=( )时,l1、l2重合
⑤α=( )时,l1⊥l2