Question

What is the domain of `y=x^3`?

Answer 1

`-oo -> +oo` There are no restrictions on `x`

Domain means all the values of `x` that may be put into the equation, to give a allowed value of `y`

Example of a restriction:
`root 2 x` has the restriction that `x` may not be negative, because square roots of negative numbers are not defined. So the domain with this function is `x>=0`
Another one is `y=1/x` where `x` cannot be `0`

For `y=x^3` there is no such restriction. `x^3` is defined for any value of `x`.