A:Somebody; he
B:Anybody; he
C:Somebody; it
D:Anybody; it
(Ⅰ)求证:平面MOE∥平面PAC;
(Ⅱ)求证:平面PAC⊥平面PCB.
对一切实数x,不等式x2+a|x|+1≥0恒成立,则实数a的取值范围是( )