Q5:
If (y+3)(y-1) – (y-2)(y-1) = r(y-1), what is the value of y?
(1) r2 = 25
(2) r = 5
A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.
Answer: E
怎么不是b么?5不行?
r=5时 方程恒等 y不知
相反,我不太理解为什么条件1推不出,r= -5时可以推出y=1的,是因为r=5的影响吗
这题是否需要在讨论一下,从(1)可得r=5 or -5,然后带入,5不行,-5可以,所以(1)是能够解决问题的,这么想怎么不对?请nn指教?
这都出的什么题,都挖这种陷阱了,太阴险啦
(y+3)(y-1)-(y-2)(y-1)=r(y-1)
可化简成:(y-1)5=r(y-1),这就不是个关于y的方程,所以不管r是不是等于5,都不知道y的值。
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