Rewrite this as √(49·10·y⁴·y·(w³)²).
Any squared term under the radical sign can be taken outside, in the form of its square root:
√a² = a; √(a²b) = a√b; etc.
Note that 49, y⁴, and (w³)² are all squares; their square roots are 7, y², and w³. Take all these outside, leaving the other (irreducible) terms inside:
So the final answer is 7y²w³√(10y)