使代数式y=(x^2+11)/(x+1)的值为整数的全体自然数x的和是( )
人气：222 ℃ 时间：2019-08-18 05:03:40
解答
y=(x²+11）/(x+1) =(x²+2x+1-2x-2+1+11)/(x+1) =[(x+1)²-2（x+1)+12]/(x+1) =x+1-2+12/(x+1） 当x=1 ,2 ,3 ,5 ,11时值为整数 所以1+2+3+5+11=22
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