`f(x) = (3x+1)/(4x-3)`

`f'(x) = [3*(4x-3) - 4*(3x+1)]/(4x-3)^2`

`or, f'(x) = -13/(4x-3)^2`

`or, f'(4) = -13/(4*4 - 3)^2`

`or, f'(4) = -13/(13)^2`

`or, f'(4) = -1/13`

``

`f(x) = (3x+1)/(4x-3)`

`f'(x) = [3*(4x-3) - 4*(3x+1)]/(4x-3)^2`

`or, f'(x) = -13/(4x-3)^2`

`or, f'(4) = -13/(4*4 - 3)^2`

`or, f'(4) = -13/(13)^2`

`or, f'(4) = -1/13`

``