我想問一個數學慨念~自認數學叻既人先好答

用戶20139

2008-03-08 12:28 am

我想問一個數學慨念
X/(X-1)=(X+2)/(X-1)
X=幾多??
另外
X/(X-1)=0
X=幾多?
仲有,咁
X*(X-1)=(X+5)*(X-1)
X=幾多?

更新1:

老友~X/(X-1)=(X+2)/(X-1) 交叉相乘 X(X-1)=(X+2)(X-1) X^2-X = X^2+X-2 -2X=-2 X=1 分母可以等於0嗎?

更新2:

must be negative姐係點解?

回答 (1)

a7day6night

2008-03-08 1:32 am

✔ 最佳答案

Q1)
X/(X-1) = (X+2)/(X-1)
X/(X-1) - (X+2)/(X-1) = 0
(X-X-2)/(X-1) = 0
-2/(X-1) = 0

Therefore X Must Infinity Big and must be negative

Q2)
X/(X-1) = 0

X Must be very small or X = 0

Q3)
X(X-1) = (X+5)(X-1)
X(X-1) - (X+5)(X-1) = 0
(X-1)(X - X -5) = 0
(X-1)(-5) = 0
(X-1) = 0
X = 1

2008-03-07 17:46:30 補充：
angus00701兄 D 數學 VERY GOOD

X/(X-1) = (X+2)/(X-1) 兩邊剩 (X-1) 會變 X(X-1)=(X+2)(X-1)？？

好利害

這題目目的係考數學慨念

1 / Infinity = 0;
Infinity / 1 = Infinity;
0 / X = 0;
X / 0 = Error!;

2008-03-07 17:55:04 補充：
Negative 負數

2008-03-07 17:59:34 補充：
忘記說

Infinite / Infinite = 1;
-infinite / Infinte = -1;

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