Answer
$23xy^2\sqrt [4] {x}$
Work Step by Step
Rewrite each radicand as the product of two factors such that you can take the 4th root of one of the factors:
$\sqrt [4] {2^4 • x^4 • x • y^8} + 7xy^2\sqrt [4] {3^4 • x}$
Take the 4th roots of terms to take them out from under the radical sign:
$2 • x • y^2\sqrt [4] {x} + 7xy^2 • 3\sqrt [4] {x}$
Multiply the coefficients of each radical:
$2xy^2\sqrt [4] {x} + 21xy^2\sqrt [4] {x}$
Combine like terms:
$23xy^2\sqrt [4] {x}$