依條數學算式怎樣解?幫幫忙呀

2007-09-10 2:28 am
Solve 2 * log10 [ sqrt ( x ) ] + log10 ( 6x - 11 ) - 1 = 0

答案:x=5/2

回答 (1)

2007-09-10 2:48 am
✔ 最佳答案
我諗你題目中的"10"係指個base 係10.
2 * log10 [ sqrt ( x ) ] + log10 ( 6x - 11 ) - 1 = 0
log [sqrt(x)]^2 + log(6x-11) - log 10 = 0
log[x(6x-11)/10] = log 1
x(6x-11)/10 = 1
6x^2 - 11x = 10
6x^2 - 11x - 10 = 0
(2x-5)(3x+2) = 0
x = 5/2 or -2/3 (rejected)
參考: me


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