Question 953517

Hi, I would really like help on how to do this question step by step. The question is about adding rational expressions in fractions. I have learned it before but have forgot some of it. The equation is x+1/x-1 - x-1/x+1. (The slash is the horizontal bar that divides the numerator and denominator) Thanks so much in advance. 
<pre>If {{{(x + 1)/(x - 1) - ((x - 1))/(x + 1)}}}, then: 
{{{((x + 1)(x + 1) - (x - 1)(x - 1))/(x - 1)(x + 1)}}} --------- Multiplying by LCD, (x - 1)(x + 1)
{{{((x^2 + 2x + 1) - (x^2 - 2x + 1))/(x - 1)(x + 1)}}}
{{{(x^2 + 2x + 1 - x^2 + 2x - 1)/(x - 1)(x + 1)}}}
{{{(x^2 - x^2 + 2x + 2x + 1 - 1)/(x - 1)(x + 1)}}}
{{{highlight_green(4x/(x - 1)(x + 1))}}}