問題: (2x+1)(x-2)=x-2
我的答法:
(2x+1)(x-2)-(x-2) =0
(x-2) [2x+1-1]=0
2x^2-4x=0
x=0 or x=2
我錯了什麼??
二次方程問題
2007-01-06 7:17 am
回答 (6)
2007-01-06 7:21 am
✔ 最佳答案
(2x+1)(x-2) = (x-2)(2x+1)(x-2)-(x-2)= 0
(x-2)(2x+1-1) = 0
2x(x-2) = 0
2x = 0 or x-2 = 0
x= 0 x = 2
你無錯呀~~~~
2007-01-06 3:08 pm
(2x+1)(x-2) = (x-2)
(2x+1)(x-2)-(x-2)= 0
(x-2)(2x+1-1) = 0
2x(x-2) = 0
2x = 0 or x-2 = 0
x= 0 x = 2
(2x+1)(x-2)-(x-2)= 0
(x-2)(2x+1-1) = 0
2x(x-2) = 0
2x = 0 or x-2 = 0
x= 0 x = 2
2007-01-06 8:29 am
(2x+1)(x-2)-(x-2) =0（先X除, 后加減 你都唔記得，等一個step都錯la)
試下咁:
(2x+1)(x-2) = x-2
2x(二次方)+x-4x-2 = x-2
2x(二次方)-3x-2 = x-2
2x(二次方)-3x = x-2+2
2x(二次方) = x+3x
2x(二次方) = 4x
x(二次方) = 4x/2
x(二次方) = 2x
x‧x = 2x (相方各取消１個ｘ）
x = 2
試下咁:
(2x+1)(x-2) = x-2
2x(二次方)+x-4x-2 = x-2
2x(二次方)-3x-2 = x-2
2x(二次方)-3x = x-2+2
2x(二次方) = x+3x
2x(二次方) = 4x
x(二次方) = 4x/2
x(二次方) = 2x
x‧x = 2x (相方各取消１個ｘ）
x = 2
2007-01-06 7:22 am
(2x+1)(x-2)=x-2
(2x+1)=(x-2)/(x-2)
2X+1=1
2x=0
x=0
(2x+1)=(x-2)/(x-2)
2X+1=1
2x=0
x=0
收錄日期: 2021-04-13 14:57:31
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20070105000051KK04586