Question 359073
Get the three terms over a common denominator. Then expand and simplfy if possible
{{{((x-3) / (x-9)) - ((x+1) / (x+9)) + ((x-117) / (x^2-81))}}}
{{{x^2 -81 = (x-9)(x+9)}}} so let's get all three terms over {{{x^2-81}}}
{{{((x-3)(x+9) / (x+9)(x-9)) - ((x+1)(x-9) / (x-9)(x+9)) + ((x-117) / (x^2-81))}}}
Now expand the first two terms
{{{((x^2+6x-27)-(x^2-8x -9)+ (x-117))/(x^2-81)}}}
Collect like terms in the numerator
{{{(15x - 135)/(x^2-81)}}}
{{{(15(x-9))/(x^2-81)}}}
Now Simplify (remember that {{{x^2 -81 = (x-9)(x+9)}}} 
{{{15/(x+9)}}}