Math problem

2007-05-24 10:29 pm
how to solve the following equation?

(x^2 - 2x) - 2x^2 + 4x - 3 =0

(5^2x - 125)^2 = 0

回答 (2)

2007-05-24 10:46 pm
✔ 最佳答案
(x^2 - 2x) - 2x^2 + 4x - 3 =0
x^2-2x+3=0
x=(2士√-8)/2
x=1士√-2
x=1士√2i


[5^(2x) - 125]^2 = 0
5^(2x)-125=0
5^(2x)=125
5^(2x)=5^3
2x=3
x=1.5

2007-05-24 14:46:33 補充:
i=√-1(虛數)
參考: me
2007-05-24 10:44 pm
1. (x^2 - 2x) - 2x^2 + 4x - 3 =0
x^2 - 2x + 3 = 0
因為 b^2 - 4ac <0 (自行驗證)
所以 x 無實數解.(但有虛數根!!!)

2. (5^2x - 125)^2 = 0
5^2x - 125 = 0
5^2x = 125
2x = log 125 / log 5
x = 3/2


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