7p^3q^3/9n^4/14p^2q/3mn^2

To simplify the expression 7p^3q^3/9n^4/14p^2q/3mn^2, we can combine the fractions by multiplying the numerators and denominators:

(7p^3q^3 * 3mn^2) / (9n^4 * 14p^2q)

This gives us:

21p^3q^3mn^2 / 126n^4p^2q

Next, we can simplify by canceling out any common factors between the numerator and denominator. In this case, we can cancel out the factors of n^2 and p:

21q^3m / 126n^2

Finally, we divide each term by 3 to get the simplified expression:

7q^3m / 42n^2