Which one of the following simplifications is incorrect?
Group of answer choices

sqrt(48x^4)*root(4)(16x^10)=8x^4root(4)(3x^2)

sqrt(4x)*sqrt(12x^8)=4x^4sqrt(3x)

sqrt(x^3)*sqrt(xy^4)= x^2y^2

root(3)(64)*sqrt(18)=12sqrt(2)