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标题: 关于x 的多项式 [打印本页]

作者: rushcynthia    时间: 2003-1-8 14:28     标题: 关于x 的多项式

16.关于x 的多项式,x^2+6x+p ,p is constant, the value of p is?
a.x^2+6x+p=(x+r)^2对于所有的x和部分的r满足 b.x^2+6x+p=(x+m)(x+n) 选a

In robert's summary,the answer should be D.which is the right?I cannot work out the second equation using my poor math knowledge .
作者: 猫猫头    时间: 2003-1-8 14:34

B中把没有X的部分统统加起来就是P了
作者: isenetlab12    时间: 2003-1-8 14:39

No, I don't agree with robert's answer.
condition(2) cannot give the answer
m=2,n=4,m=1, n=5,m=n=3, all can meet the equation, but p is different (8,5,9)
condition (1) can, since only r =3 can meet the equation.
Agree?
作者: rushcynthia    时间: 2003-1-8 14:54

x^2+6x+q=(x+m)(x+n)=x^2+(m+n)x+mn
没有x的项?refer to mn?but mn does not have specific value,how to determin q?
作者: 猫猫头    时间: 2003-1-8 15:37

如果M和N是未知数的话,答案就是A




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