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标题: 306 是选A [打印本页]

作者: XiJuan 时间: 2010-8-16 23:53
标题: 306 是选A
306

S: 2/(x+2)+3/(x+3)>1,what is the possible value of x^2?
I.1
II.4
III.9
A.I only
B.II only
C.I&II only
D.I&III only
E.I, II, & III

因为化简后X的平方小于6，X〈2.4

作者: raiy 时间: 2010-8-17 15:32
認同是 a

因為 if x^2 = 4
x = 2 or -2

when x=-2 => x+2 = 0
2/(x+2) -> undefined

same case for x^2=9, x = -3

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