Question 308993
GreAt job using the formula system, I am impressed. 

{{{ 1/x + 1/(1 + x) = -3/(x^2 + x) }}}

combine the two fractions on the left like regular fractions

{{{(x+1)/x/(x+1) + x/x/(x+1) = -3/x/(x+1)}}}
{{{(x+1+x)/x/(x+1) = -3/x/x+1}}}
{{{(2x+1+3)/x/(x+1) = 0}}}
{{{(2x+4)/x/(x+1) = 0}}}

x=-2

CHECK
*[invoke substitution "1/x + 1/(1 + x) = -3/(x^2 + x)", "x", -2 ]