Question 387058
{{{ln(x-5)+ln(x+1)=ln(40)}}}
{{{ln((x-5)(x+1))=ln(40)}}}
{{{(x-5)(x+1)=40}}}
{{{x^2-4x-5=40}}}
{{{x^2-4x-45=0}}}
{{{(x-9)(x+5)=0}}}
Two solutions:
{{{x-9=0}}}
{{{highlight(x=9)}}}
.
.
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{{{x+5=0}}}
{{{x=-5}}}
However, the ln function requires positive arguments so this solution is not valid.