若互不相等的实数a,b,c,成等差数列，且c,a,b成等比数列，且a+3b+c=10,则a=

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

A.4                  B.2                    C.-2                       D.-4

若互不相等的实数a,b,c,成等差数列，且c,a,b成等比数列，且a+3b+c=10,则a=（    ）

A. -4             B. -2              C.2               D. 4

若互不相等的实数a,b,c成等差数列，ca,ab,bc成等比数列，且

A．－8                        B．4                            C．－4                        D．8