若3n^2-n=1,求6n^3+7n^2-5n+2003的值

ilove妖精2022-10-04 11:39:541条回答

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shiguangshi 共回答了21个问题 | 采纳率85.7%: 3n^2-n=1,
6n^3+7n^2-5n+2003
=6n^3-2n^2+9n^2-5n+2003
=2n(3n^2-n)+9n^2-5n+2003
=2n*1+9n^2-5n+2003
=9n^2-3n+2003
=3(3n^2-n)+2003
=3*1+2003
=2006; 1年前

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