—Look! How _________ the market is!—Yes. There are always lots of people buying things there.
A:live
B:living
C:alive
D: lively
定义域为R的函数f(x)满足条件:
①fx1-fx2x1-x2>0,(x1,x2∈R+,x1≠x2)
②f(x)+f(﹣x)=0(x∈R);
③f(﹣3)=0.
则不等式x•f(x)<0的解集是( )