Please help to reduce the following to a quadratic equation
Please show detail steps
Thanks
4^x - 2^(x+3) - 1 =0
Reduce to Quadratic equation
2007-04-02 8:43 am
回答 (3)
2007-04-02 9:04 am
✔ 最佳答案
4^x - 2^(x+3) - 1 = 0(2^2)^x - (2^x)*(2^3) - 1 = 0
(2^x)^2 - 8*(2^x) - 1 = 0 -------------------------(1)
Let 2^x = y
Then (1) --> y^2 - 8y - 1 = 0
It is a quadratic equation
2007-04-02 01:38:46 補充：
your solution is not correct4^x cannot go forward to 2^(x x)
2007-04-02 8:54 pm
4^x - 2^(x+3) - 1 =0
2^(2x) - 2^x(8) - 1 = 0
the required equation:
k^2 - 8k - 1 = 0 ,where k = 2^x
2^(2x) - 2^x(8) - 1 = 0
the required equation:
k^2 - 8k - 1 = 0 ,where k = 2^x
參考: eason mensa
2007-04-02 9:06 am
4^x - 2^(x+3) - 1 =0
(2^2)^x - (2^x)(2^3) -1 =0
(2^x)^2 -8(2^x) - 1 = 0
let y = 2^x
y^2 -8y -1 =0
(2^2)^x - (2^x)(2^3) -1 =0
(2^x)^2 -8(2^x) - 1 = 0
let y = 2^x
y^2 -8y -1 =0
收錄日期: 2021-04-12 21:38:24
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https://hk.answers.yahoo.com/question/index?qid=20070402000051KK00188