What is the simplest form of RootIndex 3 StartRoot 27 a cubed b Superscript 7 Baseline EndRoot? 3 a b squared (RootIndex 3 StartRoot b EndRoot) 3 a b cubed (RootIndex 3 StartRoot 3 a b EndRoot) 9 a b squared (RootIndex 3 StartRoot b EndRoot) 9 a b cubed (RootIndex 3 StartRoot 3 a b EndRoot)