3 12 3(x) 12 3x+12
-- + -- ---- + ---- = -------
1 x 1(x) x x 3x+12 x^2 6x
----------------- = ----------------- ------------ ------ . ------ = ---
1 16 1(x^2) 16 1x^2 - 16 x 1x^2-16 x-4
--- - --- ------ - ---- --------------
1 x^2 1(x^2) x^2 x^2

My answer is 6x but the text states it should be 3x What am I missing?
--- ---
x-4 x-4

Your problem cannot be read properly as all your rational expressions do not show correctly.