√((25x^9y^3)/(64x^6y^11)) doing the normal division within the radical
√((25x^3)/(64y^8) then looking at the squares within the radical...
√((5^2*x^2*x)/(8^2*y^8)) now we can move out the perfect squares...
(5x/(8y^4))√x
So it is the bottom answer...