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已知四个实数成等差数列,五个实数成等比数列,则的值等于
A. B. 8 C. D.
已知四个实数成等差数列,五个实数成等比数列,
则的值为.................................................................................................... ( )
A. B. C. D.
已知四个实数成等差数列,-4,b1,b2,b3,-1五个实数成等比数列,则= ( )
A. 1 B .2 C .-1 D .±1