Answer:
64x^12 / y^20
Explanation:
(4x^3y^-5)^4
Distribute the exponential value of 4 to all terms in the parentheses.
4^4 * x^(3*4) * y^(-5*4)
Multiply each exponent.
64x^12 * y^-20
Make the negative exponent positive by making it a fraction.
64x^12 / y^20