最佳回答取４０分：一條Change of Subjet of a Formula問題

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2007-02-02 19:53:21 補充：
http://x54.xanga.com/f3cd3543c1333104256509/z73646741.gif我upload到xanga 你可以睇睇岩唔岩

2007-02-03 13:31:50 補充：
我出到最後答案啦http://x4b.xanga.com/695d320239430104433742/z73783099.gifhttp://x4b.xanga.com/695d320239430104433742/z73783099.gif自己上去睇我用計數機check 過係岩架 thx~

x+b/4a+b - x-2a/2(a+b) = b-2a/b+2a
x-x=a/(a+b)-b/4a-2a/b+2a+b
0=a/(a+b)-b/4a-2a/b+2a+b

Therefore,no solution.

(x+b)/(4a+b) - (x-2a)/2(a+b) = (b-2a)/(b+2a)
(x+b)/(4a+b)-(x-2a)/(2a+2b) = (b-2a)/(b+2a)
〔(x+b)(2a+2b)-(x-2a)(4a+b)〕/ (4a+b)(2a+2b) = (b-2a)/(b+2a)
2ax+2bx+2ab+2(b^2) - 〔4ax+bx-8(a^2)-2ab〕 / 8(a^2)+8ab+2ab+2(b^2)= (b-2a)/(b+2a)
〔-2ax+3bx+2(b^2) -8(a^2)〕 / 〔8(a^2)+10ab+2(b^2)〕= (b-2a)/(b+2a)
-2ax+3bx+2(b^2) -8(a^2) = (b-2a)/(b+2a) * 〔8(a^2)+10ab+2(b^2)〕
-2ax+3bx = ｛(b-2a)〔8(a^2)+10ab+2(b^2)〕/(b+2a)｝ -2(b^2) +8(a^2)
x(3b-2a)= 〔28(a^2)b+14a(b^2)+2(b^3)-16(a^3)/(b+2a) 〕 -2(b^2) +8(a^2)
x=｛〔28(a^2)b+14a(b^2)+2(b^3)-16(a^3)/(b+2a) 〕 -2(b^2) +8(a^2)｝ /(3b-2a)

我計左好耐，計到：

x=2a(10ab+16a二次方-b二次方)/4a二次方+b二次方

右邊: b/b-2a+2a = 1

左(2): -x-2a/2a+2b = -x-1+2b

x+b/4a+b - x-1+2b = 1
x+b/4a - x-1+2b = 1-b
x+b/4a - x+2b = 2-b
x+b/4a - x = 2+b
x/4a - x = 2
x - x = 8a
-x = 8a-x
x = 8a+x

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唔知岩唔岩, 因為有兩個x
1個正x 1個負x
兩個一齊就係等於0
所以答案可唔可以有no solution?

XB/4A+B-X-2A/2(A+B)=B-2A/B+2A
XB/4A+B-X =B-2A/B+2A+2A/2(A+B)
XB/4A+B-X =B-2A/B+2A+A(A+B)
XB/4A-X =2A-2A/B+A(A+B)
XB-4AX =4A(2A-2A/B+A(A+B))
(B-4A)X =4A.A(2-2/B+A+B)
X =4A.A(2-2/B+A+B)/(B-4A)