solve for x
(x+2)(x-4)=(a+2)(a-4)
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2010-07-14 10:37 pm
回答 (3)
2010-07-14 10:47 pm
✔ 最佳答案
As follows:圖片參考：http://i707.photobucket.com/albums/ww74/stevieg90/01-124.jpg
2010-07-14 14:47:49 補充：
http://i707.photobucket.com/albums/ww74/stevieg90/01-124.jpg
2010-07-14 11:02 pm
(x+2)(x-4)=(a+2)(a-4)
x^2-2x-8.=a^2-2a-8
x^2-a^2...=2(x-a)
(x+a)(x-a)=2(x-a)
(x+a)........=2
x.............=2-a
其實你如果THINK清楚條題目,a=x...............
..................x=2-x
............2x....=2
.................x.=1
x^2-2x-8.=a^2-2a-8
x^2-a^2...=2(x-a)
(x+a)(x-a)=2(x-a)
(x+a)........=2
x.............=2-a
其實你如果THINK清楚條題目,a=x...............
..................x=2-x
............2x....=2
.................x.=1
2010-07-14 10:52 pm
(x+2)(x-4)=(a+2)(a-4)
x^2 + 2x - 4x - 8 = a^2 + 2a - 4a - 8
x^2 - 2x = a^2 - 2a
x^2 - a^2 - 2x + 2a = 0
(x - a)(x + a) - 2(x - a) = 0
(x - a)(x + a - 2) = 0
x = a or x = 2 - a
x^2 + 2x - 4x - 8 = a^2 + 2a - 4a - 8
x^2 - 2x = a^2 - 2a
x^2 - a^2 - 2x + 2a = 0
(x - a)(x + a) - 2(x - a) = 0
(x - a)(x + a - 2) = 0
x = a or x = 2 - a
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