If 3 is the index, and there is no radicand, and inside of that radical is another radical with ten being the radicand, how could the result be 6 as the index with ten being the radicand? I thought you multiply the outer index with the inner one. In that case you would get 3, not 6.
1 answer
the inner radical has an understood index of two (square root). 3x2 makes an index of 6.