的值為

1. A.
   9
2. B.
   -9
3. C.
   3
4. D.
   -3

的值是                                      (   )

A.9                    B.-9                C.  9            D.  3

的值是                                                          （     ）

A．－2        B．2        C．        D．－

的值等于（    ）                                                                                                                                          A．7          B. -7            C. ±7           D.