Question 63739
- 4mn^2/m^-1 + 2mn^2m^-1 - 7m^3/mn^-2

=-4 m^(1+1)n^2 + 2m^(1-1)n^2 -7m^(3-1)n^2

=-4 m^2n^2 + 2n^2 -7m^2n^2

=-11m^2n^2 + 2n^2

=n^2(-11m^2 + 2)