Did I do these right?

Simplify:

129. Sqrt. y^14

y^7

131. - Sqrt. a^6

-a^3

141. Cubed Rt. 125b^15

125b^5

Before I continue, I want to make sure, firstly, that I understand what I'm doing and, secondly, that I'm distributing the fractions properly. For example:

Cubed Rt. 125b^15

I multiplied 1/3 and 15 and got 5. Should I have distributed 1/3 to the 125, too? ...Assuming I'm doing all this right...