Firstly, we can separate the factors with the variable x and the factors without it.
When we have a multiplication inside a root, we can separate them into two roots:
![\sqrt[]{36x^8}\cdot\sqrt[4]{16x^(12)}=\sqrt[]{36}\sqrt[]{x^8}\cdot\sqrt[4]{16}\sqrt[4]{x^(12)}=\sqrt[]{36}\sqrt[4]{16}\cdot\sqrt[]{x^8}\sqrt[4]{x^(12)}](https://img.qammunity.org/2023/formulas/mathematics/college/95ybx98b9ku3k8snoahx7aj0r4j8hkd06s.png)
For the factors without x, we can see that 36 is the same as 6 times 6 and 16 is the same as 2 * 2 * 2 * 2:
![\sqrt[]{36}\sqrt[4]{16}\cdot\sqrt[]{x^8}\sqrt[4]{x^(12)}=\sqrt[]{6^2}\sqrt[4]{2^4}\cdot\sqrt[]{x^8}\sqrt[4]{x^(12)}](https://img.qammunity.org/2023/formulas/mathematics/college/90yn86xnmtkpp6t031ig8co7bmf62x9ykg.png)
Now, we can apply the following property for all roots:
![\sqrt[c]{b^a}=b^{(a)/(c)}](https://img.qammunity.org/2023/formulas/mathematics/college/us4kev5l29uqfz2vxih936iev4ln832ywa.png)
So, we have:
![\sqrt[]{6^2}\sqrt[4]{2^4}\cdot\sqrt[]{x^8}\sqrt[4]{x^(12)}=6^{(2)/(2)}2^{(4)/(4)}\cdot x^{(8)/(2)}x^{(12)/(4)}=6\cdot2\cdot x^4x^3=12\cdot x^4x^3](https://img.qammunity.org/2023/formulas/mathematics/college/uykhju8ng69g5a7g0xqineaexjb2frs2ve.png)
Now, we can use the property:

So:

So, the simplest form is:
