simplify the sum and diffrences and is there any restrictions (3x/x^2-4)+(6/x+2)

3x/[x^2 - 4] + 6/[x + 2]   =

3x / [(x + 2)(x -2)] +  6/[x + 2]        get a common denomonator......

3x/[(x + 2)(x -2)] + 6[x -2] / [(x + 2)(x - 2)]   =

[3x + 6x - 12] /  [(x + 2) (x -2)]  =

[9x - 12] / [ (x + 2) ( x- 2)]      and x cannot equal 2 or -2  [those make the denominator = 0 ]