Question 999796
4m^-6*4m^9*4m^7/(4m^2-5n^-3)=
64m^10/(4m^2-5n^-3)
can multiply top and bottom by (4m^2+5n^3)/(4m^2+5n^3). The conjugate removes the negative exponent.
256m^12+320m^10n^3/(16m^4-25).
One may factor a 64 out of the numerator, but this can't be simplified.  The denominator can factor into (4m^2+5)(4m^2-5), but those can't cancel anything in the numerator.