I find it easiest to put these in expnential form and then simplify
√ 27x^11y^6 =
(3^3)^(1/2) * (x^11)^(1/2) * (y^6)^(1/2) =
(3)^(3/2) * (x)^11/2 * (y)^3
Now.....we can find out how many powers of each thing come out of the radical and how many powers stay in by this procedure :
Divide 3/2 and express as a mixed number = 1 + 1/2
The whole number tells how many powers of 3 come out of the radical = 3^1
The numerator tells how many powers of 3 stay in the radical = 3^1
Similarly
11/2 = 5 + 1/2
5 powers of x come out......1 power stays in
And
3 = 3
We have no mixed number.....so 3 powers of y come out and there remain 0 that stay in
So....we have
3^1* x^5 * y^3 √ [ 3^1 * x^1 ] =
3x^5y^3 √ [ 3x ]