# Solving Logarithims

• Jun 8th 2010, 01:00 PM
SouthernDiva
Solving Logarithims
(Headbang) I have two problems that I don't understand. Either they are written wrong on this worksheet or I am really that math dumb.
I have looked online for some problems similar, and I am coming up empty handed.

1. Solve for y in terms of x: ln y + .6931 = 9 ln x

2. Slove equation: log (x+9)=1-log x

Any help is greatly appreciated.
• Jun 8th 2010, 01:10 PM
earboth
Quote:

Originally Posted by SouthernDiva
(Headbang) I have two problems that I don't understand. Either they are written wrong on this worksheet or I am really that math dumb.
I have looked online for some problems similar, and I am coming up empty handed.

1. Solve for y in terms of x: ln y + .6931 = 9 ln x

2. Slove equation: log (x+9)=1-log x

Any help is greatly appreciated.

1. $0.6931 \approx \ln(2)$

2. The first equation becomes:

$\ln(y)=9 \ln(x)-\ln(2)$

$\ln(y)=\ln\left(\frac{x^9}2\right)$

Now use both sides as exponents to the base e:

$e^{\ln(y)}=e^{\ln\left(\frac{x^9}2\right)}$

$y = \frac{x^9}2$

Do the 2nd equation in just the same way.