Question 84252
(-2x^4)^3(-4x^2y^6)^3
-2^3=-8
-4^3=-64
-8*-64=512
(x^4)^3=x^12
(x^2)^3=x^6
x^12*x^6=x^18 your x^12 is also incorrect!
(y^6)^3=y^18 powers times powers needs to be multiplied.
512x^18y^18 is the correct answer.