Verified Answer :

\(\sqrt{400i^8j^4k^6}=\sqrt{400}\cdot\sqrt{i^8}\cdot\sqrt{j^4}\cdot\sqrt{k^6}=20i^4j^2|k^3|\to\boxed{A.}\)

Answer:

a) \(20i^4j^2k^3\)

Step-by-step explanation:

Given expression is,

\(\sqrt{400i^8j^4k^6}\)

\(=\sqrt{400(i^4)^2(j^2)^2(k^3)^2}\)     ( \(a^{mn}=(a^m)^n\)  )

\(=\sqrt{(20)^2(i^4)^2(j^2)^2(k^3)^2}\)    (  \((20)^2 = 400\)  )

\(=\sqrt{(20i^4j^2k^3)^2}\)        (  \(a^m.b^m=(ab)^m\) )

\(=((20i^4j^2k^3)^2)^{\frac{1}{2}}\)    ( \(\sqrt{a}=(a)^{\frac{1}{2}\)  )

\(=(20i^4j^2k^3)^{2\times \frac{1}{2}}\)    

\(=20i^4j^2k^3\)

Option a) is correct.