1.命题“3x∈R,√x+1>0”的否定是A.3x∈R,x+1≤0B.Hx∈R,x+1≤0C.Hx∈R,x+1>0D.HxtR,Wx+1≤02.设集合A={x|(x+1)(x-12)≤0},B={x|x>6},则A∩B=A(6,12)B.[12,+o∞)C.(6,12]D.[-1,+o)