Question 419876
a general rule is:
{{{ log(a*b) = log(a) + log(b) }}}
For example:
{{{ log (10*10*10) = log(10) + log(10) + log(10) }}}
Just work the rule backwards
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{{{ ln(x) + ln(x + 3) = 1 }}}
{{{ ln( x*(x + 3)) = 1 }}}
{{{ ln( x^2 + 3x) = 1 }}}
Now use the general rule
{{{ log(a,b) = c }}} then,
{{{ a^c = b }}}
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{{{ e^1 = x^2 + 3x }}}
{{{ x^2 + 3x - e = 0}}}
{{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}} 
{{{a = 1}}}
{{{b = 3}}}
{{{c =-e}}}
{{{x = (-3 +- sqrt( 3^2-4*1*(-e) ))/(2*1) }}}  
{{{x = (-3 +- sqrt( 9 + 4e ))/2 }}}  answer