Answer:
It's the first, third and the last one.
Explanation:
We have to write of the form that y which represents the second number in the set is the cube of x which represents all the first numbers in the set so in first for example 64 which is y as its the second number in the set is the cube of 4 which is x means the first number in the set.
I hope you understood I tried my best to explain.