已知

则=

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

已知,,则A∩B等于

A．{x|x∈R}                              B．

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

A.(-2,-3)                     B.(2,3)

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

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

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

已知点A(0, –1)，点B在直线x–y+1=0上，直线AB垂直于直线x+2y–3=0，则点B的坐标是(    )

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