Question 1135174
{{{4*x/(x^2-1)+3*x/(1-x)-4/(x-1)}}}


understand that {{{(-1)(1-x)=-1+x=x-1}}}


Now your expression is equivalent to
{{{4*x/(x^2-1)-3*x/(x-1)-4/(x-1)}}}


Note that simplest common denominator is  {{{(x+1)(x-1)}}}.
Bring each separate rational expression to "higher terms" for this denominator.