多项式x的平方+kx+20能在整数范围内分解因式,则k可取的整数值有6个 k为什么是20的因数的和
人气：102 ℃ 时间：2019-09-16 19:22:35
解答
能在整数范围内分解因式,k必定是整数
设分解成（x+a）（x+b）,则（x+a）（x+b）=x的平方+（a+b）x+ab=x的平方+kx+20
即ab=20,a+b=k
所以,k是20的因数的和
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