1.D因为CuA={x∈Zx2≤4}={-2,-1,0,1,2},故选D.2.C命题p:3x∈R,使得3x2一2|x十5=0,则命题p的否定是Hx∈R,3x2一2|x|十5≠0,故选C.3.Bab=名×2a×子×2少=号当且仅当2a=6,即a=-号6=5或a号6=5时等号成立.故选B.