Question 870274
{{{(log((x)))^2+4*log((x))-9=0}}}
{{{u=log((x))}}}
{{{u^2+4u-9=0}}}
Complete the square,
{{{(u^2+4u+4)-9=4}}}
{{{(u+2)^2=13}}}
{{{u+2 = 0 +- sqrt(13)}}}
{{{u=-2 +- sqrt(13)}}}
{{{log((x))=-2 +- sqrt(13)}}}
{{{x=10^(-2+-sqrt(13))}}}