题目内容
已知2a=3b=k(k≠1),且2a+b=ab,则实数k的值为( )
| A.6 | B.9 | C.12 | D.18 |
∵2a=3b=k(k≠1),
∴a=log2k,b=log3k,
∴
=logk2,
=logk3,
∵2a+b=ab,
∴
+
=2logk3+logk2
=logk9+logk2
=logk18=1,
∴k=18.
故选D.
∴a=log2k,b=log3k,
∴
| 1 |
| a |
| 1 |
| b |
∵2a+b=ab,
∴
| 2 |
| b |
| 1 |
| a |
=logk9+logk2
=logk18=1,
∴k=18.
故选D.
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