已知

則=

  (A)        (B)               (C) 1            (D) 0

已知,,則A∩B等于

A．{x|x∈R}                              B．

C．{(0,0),(1,1)}                            D．

 

已知點A(0,-1),點B在直線x-y+1=0上,若直線AB垂直于直線x+2y-3=0,則點B的坐標(biāo)是…(    )

A.(-2,-3)                     B.(2,3)

C.(2,1)                      D.(-2,-1)

已知點A(0，-1)，點B在直線x-y+1=0上，若直線AB垂直于直線x+2y-3=0，則B點坐標(biāo)是(    )

A.(-2,3)                                 B.(2,1)

C.(2,3)                                  D.(-2,-1)

已知點A(0, –1)，點B在直線x–y+1=0上，直線AB垂直于直線x+2y–3=0，則點B的坐標(biāo)是(    )

A．(–2, –3)         B．(2, 3)             C．(2, 1)             D．(–2, 1)