If a, b >= 0a,b≥0 then sqrt(ab) = sqrt(a)sqrt(b)√ab=√a√b and sqrt(a/b) = sqrt(a)/sqrt(b)√ab=√a√b
sqrt((x^6)/27) = sqrt((3x^6)/81) = (sqrt(x^6)sqrt(3))/sqrt(81) = (abs(x^3)sqrt(3))/9 = sqrt(3)/9 abs(x^3)√x627=√3x681=√x6√3√81=∣∣x3∣∣√39=√39∣∣x3∣∣
Note abs(x^3)∣∣x3∣∣, not x^3x3.
If x < 0x<0 then x^3 < 0x3<0, but sqrt(x^6) > 0√x6>0 since sqrt√ denotes the positive square root.