Multiply the following polynomials: (7mn - 4n^3)(2m^5 + 5mn - 12)
step by step

(7mn - 4n^3) (2m^5 + 5mn - 12)

=14m^6n + 35m^2n^2 - 84mn - 8m^5n^3 - 20mn^4 + 48n^3

=14m^6n + 8m^5n^2 + 35m^2n^2 + 20mn^4 - 84mn + 48n^3

This:

14m^6n + 8m^5n^2 + 35m^2n^2 + 20mn^4 - 84mn + 48n^3

is the write way to write your answer.