X Y

1 1
2 8
3 27
4 64
5 125
6 216

is thiis linear or nonn linear

The given data appears to be non-linear, as the values of Y do not increase or decrease at a constant rate.

is it a function or not

Yes, the given data can be considered a function. A function is a relationship between two sets of variables, in this case, X and Y. In the given data, each value of X is associated with a unique value of Y, which satisfies the definition of a function.