Question 40282
[(-12x^5y^-4)/(3x^-2y)]^-2 
First rewrite the fraction, as follows:
{[(-12x^5)/(y^4)]/[(3y)/x^2]-2}^
=Invert the denominator and multiply 
{[(-12x^5)/y^4]*[x^2/3y]}^-2
={-12x^7/3y^5]^-2
=[-4x^7/y^5]^-2
=y^10/16y^14
Cheers,
Stan H.