Hello

First lets start factoring:

$\large \frac { 3x }{ x-a } +\frac { x(x-3a) }{ (x+a)(x-a) }$

Then:

$\large \frac { 3x(x+a)+x²-3ax }{ (x+a)(x-a) }$

Then:

$\large \frac { 3x²+x²+3ax-3ax }{ (x+a)(x-a) }$

Then:

$\large \frac { 4x² }{ (x+a)(x-a) }$

Then:

$\large \frac { 4(4)² }{ 4+2(4-2) }$

$\large \frac { 64 }{ 12 } \quad \therefore \quad \frac { 16 }{ 3 }$

$\large \frac { 16 }{ 3 } \quad = \boxed{5.33333 }$

Thanks!