## Intermediate Algebra (6th Edition)

The product rule holds that $\sqrt[n] a\times\sqrt[n] b=\sqrt[n] (ab)$ (where $\sqrt[n] a$ and $\sqrt[n] b$ are real numbers). Therefore, $\sqrt[4] 8\times\sqrt[4] 2=\sqrt[4] (8\times2)=\sqrt [4] 16=2$ We know this because $2^{4}=16$.