absolute values

Case 1 :
假設 3 - 2x ≧ 0
3 -2x = 6x -5
8 = 8x
x = 1
代入假設 3 - 2x = 3 - 2 (1) = 1≧0 (合符假設)

Case 2 :
假設 3 - 2x ＜ 0
- (3-2x) = 6x - 5
-3 + 2x = 6x - 5
2 = 4x
x = 1/2
代入假設, 3 - 2x = 3 - 2 (1/2) = 3 - 1 = 2 不是 ＜ 0 (不合符假設)

所以只有 x = 1 是答案.

l3-2xl=6x-5
3-2x=6x-5 or 3-2x= -6x+5
-8x= -8 4x=2
x=1 x=1/2

={1 , 1/2}

3-2x = -(6x-5) or 3-2x = 6x-5
3-2x = -6x+5 8x = 8
4x =2 x = 1
x = 1/2

2006-10-31 07:43:20 補充：
x 會有2個answer......不過上面咁打唔係咁清楚....我分開2個case 打....Case 1 :l3-2xl=6x-5 3-2x = 6x-58x = 8x = 1Case 2:l3-2xl=6x-53-2x = -(6x-5)4x =2 x = 1/2