Question 617695
{{{(1/b) - (b/(b-1)) = 2}}}

{{{(1/b)*((b-1)/(b-1))-(b/(b-1))*(b/b)-(2*b*(b-1))/(b*(b-1))=0}}}


{{{(-3b^2+3b-1)/(b*(b-1))=0}}}

Only the numerator contributes solutions so...


{{{b = (-3 +- sqrt( (3)^2-4*(-3)*(-1)))/(2*(-1)) }}} 


which simplifies to...


{{{b = (1 +- sqrt( -3))/2 }}}