Answer:
[tex]y \sqrt{y} [/tex]
Step-by-step explanation:
The given expresion is
[tex] \sqrt{ {y}^{3} } + \sqrt{4 {y}^{3} } - 2y \sqrt{y} [/tex]
We need to simplify the first two terms by removing the perfect squares under the radical sign.
[tex] \sqrt{ {y}^{2} \times y} + \sqrt{4 {y}^{2} \times y } - 2y \sqrt{y} [/tex]
[tex]y \sqrt{y} + 2y \sqrt{y} - 2y \sqrt{y} [/tex]
The last two terms zero pairs, they will simplify to zero.
[tex]y \sqrt{y} + 0[/tex]
The final answer is
[tex]y \sqrt{y} [/tex]