Sqrt(27a^9). Why is 3a^3sqrt(3) incorrect. And why 3a^4sqrt(3a) is correct? Thanks guys! Sorry for the trouble.
http://www.cymath.com/answer.php?q=sqrt(27a%5E9)
sqrt(27a^9) → sqrt(9*3*a^8*a) → sqrt(3^2*(a^4)^2*3a) → 3a^4*sqrt(3a)
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+1836 
