9.已知aaa,bbb,ccc满足2−a=a+22^{-a}=a+22−a=a+2,b+log2b=−2b+\log _{2}b=-2b+log2b=−2,c3−c−2=0c^{3}-c-2=0c3−c−2=0,则aaa,bbb,ccc的大小关系为((( )))