题目内容
计算3n•( )=-9n+1,则括号内应填入的式子为( )
| A.3n+1 | B.3n+2 | C.-3n+2 | D.-3n+1 |
∵-9n+1=-(32)n+1=-32n+2=-3n+n+2=3n•(-3n+2),
∴括号内应填入的式子为-3n+2.
故选C.
∴括号内应填入的式子为-3n+2.
故选C.
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题目内容
| A.3n+1 | B.3n+2 | C.-3n+2 | D.-3n+1 |