Respuesta :

( 3x - 12 / 9x^2 ) ÷ ( x - 4 / 3x ) =

( 3x - 12 / 9x^2 ) × ( 3x / x - 4 ) =

( 3 ( x - 4 ) / 3 × 3x × x ) × ( 3x / x - 4 ) =

( x - 4 / 3x × x ) × ( 3x / x - 4 ) =

( x - 4 ) × 3x / ( x - 4 ) × 3x × x =

1 / x

Thus the correct answer is option A .