A.{x|x≤2ab或x≥a²＋b²}                                      B.{x|x＜2ab或x≥a²＋b²}

C.{x|x＜2ab或x＞a²＋b²}                                      D.{x|2ab＜x≤a²＋b²}

不等式≤0的解集是

A.{x|1≤x＜2}                                                 B.{x|1＜x＜2或x=－3}

C.{x|1≤x＜2或x=－3}                                          D.{x|1≤x≤2或x=－3}

A.{x|x＜0或1＜x≤或x≥10}

B.{x|x＜1且x≠0或3≤x≤10}

C.{x|0＜x＜1或3＜x＜10}

D.{x|0＜x＜1或3＜x＜10}

不等式≥0的解集是（    ）

   A．{x|x＜-1或x＞1}                        B．{x|x＜-1或x≥1}

   C．{x|x＜-1且x≥1}                      D．{x|x≥1}