2007-12-02 10:04:16 · 5 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
Take log as log to base ten.
log [ x / (x + 3) ] = - 1
[ x / (x + 3) ] = 10^(-1)
x / (x + 3) = 1 / 10
10x = x + 3
9x = 3
x = 1/3
2007-12-02 10:17:14 · answer #1 · answered by Como 7 · 3⤊ 1⤋
log (x+3) + log x =a million combine the left area log(x(x + 3)) = a million replace to exponential style 10^a million = x^2 + 3x x^2 + 3x - 10 = 0 component (x + 5)(x - 2) = 0 recommendations x = -5, 2 forget approximately approximately x = -5, and the respond is x = 2.
2016-11-13 07:20:39 · answer #2 · answered by ? 4 · 0⤊ 0⤋
I assume that those are common logs (base 10).
If yes, then your answer is x = 1/3
[You can convince yourself that this is correct by testing it with a calculator.]
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Essential to solution is knowing that log a - log b = log(a/b)
and that if log base 10 of A = x, then 10^x = A
logx - log(x+3) = -1
log [x/(x+3)] = -1
10^(-1) = x/(x+3)
Take the reciprocal of each side; solve for x.
2007-12-02 10:12:08 · answer #3 · answered by answerING 6 · 2⤊ 1⤋
-4 + 3 = -1
2007-12-02 10:11:47 · answer #4 · answered by :D 4 · 0⤊ 3⤋
log x - log(x + 3) = -1, so
x/(x + 3) = 1/10, so
x = (x + 3)/10, so
10x = x + 3, so
9x = 3, so
x = 3/9, so
x = 1/3.
Hope this helps, Twiggy
2007-12-02 10:20:33 · answer #5 · answered by Twiggy 7 · 0⤊ 2⤋