Please show all clear steps, thank you.
Solve for x
1) logX = 2 + log5
2) (log X base 2) + log (X-6) base 2 = 4
3) log (2x^2) base a = (2log 6 base a) - log 2 base a
4) 2^(x+1) = 28
This help means a lot to me, thank you! ^,^
Logarithms高手please come in
2015-02-03 1:53 pm
回答 (2)
2015-02-03 5:36 pm
✔ 最佳答案
log x = 2 + log 5log x - log 5 = 2
log (x / 5) = 2
x / 5 = 10^2 = 100
x = 500
log x base 2 + log (x - 6) base 2 = 4
log [x(x - 6)] base 2 = 4
x(x - 6) = 2^4 = 16
x^2 - 6x - 16 = 0
x = 8 or x = -2(rejected)
so, x = 8
log (2x^2) base a = 2 log 6 base a - log 2 base a
log (2x^2) base a = log 6^2 base a - log 2 base a
log (2x^2) base a = log (6^2 / 2) base a = log 18 base a
2x^2 = 18
x^2 = 9
x = 3 or x = -3
2^(x + 1) = 28
log 2^(x + 1) = log 28
(x + 1)log 2 = log 28
x + 1 = log28 / log2 = 4.81
x = 3.81
參考: knowledge
2015-02-03 6:44 pm
2^(x + 1) = 28
log 2^(x + 1) = log 28
(x + 1)log 2 = log 28
x + 1 = log28 / log2 = 4.81
x = 3.81
log 2^(x + 1) = log 28
(x + 1)log 2 = log 28
x + 1 = log28 / log2 = 4.81
x = 3.81
收錄日期: 2021-04-15 18:07:41
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