# Math Help - equations

1. ## equations

Find the solution of the logarithmic equation

&; Find the solution of the logarithmic equation

?????? no clue!

2. Originally Posted by evinez
Find the solution of the logarithmic equation

$log_2(x^2 - 5x - 20) = 2$

$x^2 - 5x - 20 = 2^2 = 4$

etc.

-Dan

3. Originally Posted by evinez

$log(x) + log(x - 20) = log(7x)$

$log(x(x - 20)) = log(7x)$

$x(x - 20) = 7x$

etc.

-Dan

4. Hello,

For the second one, remember that $\log(a)+\log(b)=\log(a+b)$

Then if $\log(x)=\log(y)$, $x=y$

remember that x has to be positive and superior to 20 as x and x-20 have to be positive