想問大家(±√4)(±√4)=??▼▼▼▼▼

±√4 = +2 or ±√4 = -2

所以 :
(±√4)(±√4) =(+2)(+2) 或 (±√4)(±√4) =(+2)(-2) 或 (±√4)(±√4) =(-2)(+2) 或 (±√4)(±√4) =(-2)(-2)

(±√4)(±√4) = +4 或 (±√4)(±√4) = -4或 (±√4)(±√4) = -4或 (±√4)(±√4) = +4

答案是： B) 4 或 -4

I agree with sioieng's answer.

Suppose a = ±√4 and b = ±√4
That means (a = √4 or a = -√4) and (b = √4 or b = -√4)

Then ab = (±√4)(±√4) = 4 or -4
It is NOT (±√4)^2 !

I agree with the answer of 星期天.
(±√4)(±√4) is (+√4)(+√4) and (-√4)(-√4)
It is not to be considered (+√4)(-√4) or (-√4)(+√4).
We can only take the signs in same position (the up one or the down one)
Therefore, there are two answers and both of them are 4 (Choice A)

2012-06-11 17:12:59 補充：
I agree with the answer of 星期天.
(±√4)(±√4) are (+√4)(+√4) and (-√4)(-√4)
It is not to be considered (+√4)(-√4) or (-√4)(+√4).
We can only take the signs in same position (the up one or the down one)
Therefore, there are two answers and both of them are 4 (Choice A)

2012-06-11 17:17:20 補充：
(the up ones or the down ones)

計算 (±√4)(±√4) 是兩條數.
一條是 (+√4)(+√4) = 4 ;
另一條是 (-√4)(-√4) = 4.
兩條的答案都是 4. (A)

2012-06-03 10:08:51 補充：
如果是計算 (Ŧ√4)(±√4)
這亦是兩條數.
一條是 (-√4)(+√4) = -4 ;
另一條是 (+√4)(-√4) = -4.
兩條的答案都是 -4.