A.0                                                                 B.1

C.2                                                                 D.3

(1)“全等三角形面积相等”的逆命题;

(2)“正三角形的三个内角都是60°”的否命题;

(3)“若k＜0,则方程x²+(2k+1)x+k=0必有两相异实数根”的逆否命题.

其中真命题的个数为(    )

A.0                                     B.1

C.2                                     D.3

①f（x）的解析式为f(x)=x³-4x，x∈[-2，2]；②f（x）的极值点有且仅有一个；③f（x）的最大值与最小值之和等于零.

其中正确的命题个数为

A.0                                                 B.1

C.2                                                 D.3

A.0                                     B.1

C.2                                     D.3

化简的值为 (    )

A.0              B.-             C.2               D.