Question 13567
ln(x) + ln(x-7) = ln(5x)
{{{ln(x*(x-7)) = ln(5x)}}}
{{{ln(x*x-x*7) = ln(5x)}}}
{{{ln(x^2-7x) = ln(5x)}}}
So:
{{{x^2-7x = 5x}}}
{{{x^2-7x-5x= 0}}}
{{{x^2-12x= 0}}}
{{{x(x-12)= 0}}}
{{{x=0}}} or {{{x-12=0}}} -----> x = 12

x = 12 is solution

OK