Question 141631
Remember: {{{log(b,(x))-log(b,(y))=log(b,(x/y))}}}, so:


{{{log(e,(x))-log(e,(x+7))=log(e,(x/(x+7)))=-1}}}, but also:


If {{{y=log(b,(x))}}} then {{{b^y=x}}}, so:


If {{{log(e,(x/(x+7)))=-1}}} then {{{e^(-1)=x/(x+7)}}}


{{{1/e=x/(x+7)}}}


{{{(x+7)/x=e}}}


{{{x+7=ex}}}


{{{x-ex=-7}}}


{{{(1-e)x=-7}}}


{{{x=7/(e-1)}}}