ANSWER
![40xy\sqrt[]{21}](https://img.qammunity.org/2023/formulas/mathematics/high-school/sz8yw8u0dkndwrfzy8kfygnnuk64tt1bs5.png)
Step-by-step explanation
We want to simplify the radical expression given:
![(5\sqrt[]{2y})(4\sqrt[]{7xy})(\sqrt[]{6x})](https://img.qammunity.org/2023/formulas/mathematics/high-school/ac14vs2is7qc6bv33c3ym1qmj45eu8xofh.png)
First, separate the terms outside the radicals and the terms inside the radicals:
![5\cdot4\cdot\sqrt[]{2y}\cdot\sqrt[]{7xy}\cdot\sqrt[]{6x}](https://img.qammunity.org/2023/formulas/mathematics/high-school/6cgix1ds4z9pyc9fhsnhqkux9iy3z44lzk.png)
Since all the radicals are square roots, we can multiply all the terms inside the radicals:
![5\cdot4\cdot\sqrt[]{2y\cdot7xy\cdot6x}](https://img.qammunity.org/2023/formulas/mathematics/high-school/seclj2lllf35tgqj621edsks6vdlvmhu2w.png)
Simplify:
![20\cdot\sqrt[]{84\cdot x^2\cdot y^2}](https://img.qammunity.org/2023/formulas/mathematics/high-school/v771u7gqtas1vge53f13g3nncak78y6wgy.png)
Now, express the terms in the radicals as a product of their factors in order to simplify:
![\begin{gathered} 20\cdot\sqrt[]{2\cdot2\cdot3\cdot7\cdot x\cdot x\cdot y\cdot y} \\ 20\cdot\sqrt[]{2^2\cdot3\cdot7\cdot x^2\cdot y^2} \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/high-school/qxirjvkm8ci9mkoabeb64bx22na72s6ica.png)
Simplify by finding the square root of factors that are repeated in the square root:
![\begin{gathered} 20\cdot2\cdot x\cdot y\cdot\sqrt[]{3\cdot7} \\ \Rightarrow40xy\sqrt[]{21} \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/high-school/7gvxgn0cp0xquxgkkygqvmb2aeibepqomj.png)
That is the answer.