Simplify 3 fourth root of 16y+5 fourth root of y-2 fourth root of 81y

$3 \sqrt[4]{16 y} + 5 \sqrt[4]{y} - 2 \sqrt[4]{81 y}$

Simplify each term.

Rewrite $16$ as $2^{4}$ .

$3 \sqrt[4]{2^{4} y} + 5 \sqrt[4]{y} - 2 \sqrt[4]{81 y}$

Pull terms out from under the radical.

$3 (2 \sqrt[4]{y}) + 5 \sqrt[4]{y} - 2 \sqrt[4]{81 y}$

Multiply $2$ by $3$ .

$6 \sqrt[4]{y} + 5 \sqrt[4]{y} - 2 \sqrt[4]{81 y}$

Rewrite $81$ as $3^{4}$ .

$6 \sqrt[4]{y} + 5 \sqrt[4]{y} - 2 \sqrt[4]{3^{4} y}$

Pull terms out from under the radical.

$6 \sqrt[4]{y} + 5 \sqrt[4]{y} - 2 (3 \sqrt[4]{y})$

Multiply $3$ by $- 2$ .

$6 \sqrt[4]{y} + 5 \sqrt[4]{y} - 6 \sqrt[4]{y}$

Combine the opposite terms in $6 \sqrt[4]{y} + 5 \sqrt[4]{y} - 6 \sqrt[4]{y}$ .

Subtract $6 \sqrt[4]{y}$ from $6 \sqrt[4]{y}$ .

$0 + 5 \sqrt[4]{y}$

Add $0$ and $5 \sqrt[4]{y}$ .

$5 \sqrt[4]{y}$