计算3n•( )=-9n+1,则括号内应填入的式子为( )A.3n+1B.3n+2C.-3n+2D.-3n+1
题型:单选题难度:简单来源:不详
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 |
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答案
∵-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. |
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