數學題,10分

2007-10-11 2:33 am
4. x/3 - x/2 = 1
(x/3 - x/2) X 6 = 1 X 6
2x - 3x = 6
-x = 6
x = -6

WHY 係2x - 3x  唔係3x - 2x 既

回答 (3)

2007-10-11 2:40 am
✔ 最佳答案
因為 (x/3 - x/2) X 6 = 1 X 6
呢個step係做緊通分母
如果就咁睇 (x/3 - x/2) 呢一舊
(x/3 - x/2)
=2x/6-3x/6
=(2x-3x)6
就會同你 2x - 3x 一樣

唔明可以再問我 =]

2007-10-10 18:42:24 補充:
(x/3 - x/2) X 6 = 1 X 6呢個 step 點解要乘 6 呢?就係因為我地唔想再要個分母而 6 係 2 同 3 既共同 factor當 x/3 乘 6 就會變 2x當 x/2 乘 6 就會變 3x所以, 係2x - 3x  唔係3x - 2x 

2007-10-10 21:51:38 補充:
唔該 shirley161718唔好 copy 我d answer!
2007-10-11 3:19 am
(x/3 - x/2)

=2x/6-3x/6

=(2x-3x)6

就會同你 2x - 3x 一樣
2007-10-11 2:41 am
你而家係通分母...
(X/3)*6=2X...(X/2)*6=3X
所以個答案咪係2X-3X
參考: ME=]]


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