Simplify:

[1 / (x-3) ] + [ (4/x) / (4/x) ] - [1 / (x-3) ]

To simplify the expression, we can check if there are terms that are needed to be added or subtracted. In this case, there are none. we can multiply x * (x-3) to the denominator and numerator resulting to

[x + 4 * (x-3) ] / [4 * ((x-3)) - x] = 5x - 12 / 3x - 12.

the final answer is 5x - 12 / 3x - 12.