Logarithm question heeeeelp! (1 Viewer)

zazzy1234 · Jun 4, 2009

i found this question and don't know how 2 solve it please help!!

a. log(8x+2)-log(3x-4)=log5

b. log 125= 3log x
8 8

please heallllllllllp!

madsam · Jun 4, 2009

a. log(8x+2)-log(3x-4)=log5

b. log 125= 3log x
8 8

a) Ln(8x + 2) - ln(3x-4)
= ln((8x+2)/(3x-4) = ln5

8x+2/3x-4 = 5

8x + 2 = 15x -20
22 = 7x
x = 22/7

ln125 = ln(5^3) = 3ln5

Or close enough

Drongoski · Jun 4, 2009

zazzy: would u please try not posting yr questions in colour; it's very hard to read.

$Q1)\\ \\ log(8x+2) \ -\ log(3x-4)\ \ =\ \ log\ 5 \ \Rightarrow log\frac{8x+2}{3x-4}\ =\ log\ 5 \\ \\ \Rightarrow \ \ \frac{8x+2}{3x-4}\ =\ 5\ \ \Rightarrow 7x\ =\ 22\ \Rightarrow \ x\ =\ \frac{22}{7}\ \ (???)\\ \\ \\ Q2)\\ \\ log \ 125\ =\ 3\ log\ x\ \ \Rightarrow \ \ log\ x^{3}\ =\ log\ 5^{3}\ \ \Rightarrow \ \ x\ =\ 5$

zazzy1234 · Jun 4, 2009

im sori for the colour thing, but thanx guys 4 answering ma questions

Logarithm question heeeeelp! (1 Viewer)

zazzy1234

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madsam

God among men

Drongoski

Well-Known Member

zazzy1234

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