Question 924629
{{{ ln( x-1 ) + ln( x+2 ) = 1 }}}
{{{ ln( (x-1 )*( x+2 ) ) = ln( e ) }}}
{{{ ( x-1 )*( x+2 ) = e }}}
{{{ x^2 - x + 2x - 2 = e }}}
{{{ x^2 + x - ( 2 + e ) = 0 }}}
-------------------------
{{{ x = (-b +- sqrt( b^2 - 4*a*c )) / (2*a) }}}
{{{ a = 1 }}}
{{{ b = 1 }}}
{{{ c = -2 -e }}}
---------------
Use quadratic formula
{{{ x = (-1 +- sqrt( 1^2 - 4*1*(-2-e) )) / (2*1) }}} 
{{{ x = (-1 +- sqrt( 1 + 8 + 4*e )) / 2 }}} 
{{{ x = (-1 +- sqrt( 9 + 4*e )) / 2 }}} 
{{{ x = (-1 +- sqrt( 9 + 10.8731 )) / 2 }}} 
{{{ x = (-1 +- sqrt(  19.8731 )) / 2 }}} 
{{{ x = (-1 +- 4.4579) / 2 }}} 
{{{ x = 3.4579 / 2 }}}
{{{ x = 1.729 }}}
and
{{{ x = ( -5.4579) / 2 }}}
{{{ x = -2.729 }}}
---------------------
check:
{{{ ln( x-1 ) + ln( x+2 ) = 1 }}}
{{{ ln( 1.729-1 ) + ln( 1.729+2 ) = 1 }}}
{{{ ln( .729 ) + ln( 3.729 ) = 1 }}}
{{{ -.31608 + 1.31614 = 1 }}}
{{{ 1.00006 = 1 }}}
close enough
You can check the other root