Answer
The function is not one-to-one.
Work Step by Step
A one to one function is a function in which each x-value corresponds to one y-value and each y-value corresponds to one x-value. In the given function, a y-value may correspond to more than one x-value. For instance, y is $\sqrt5$ for both $x=-1$ and $x=1$.
Therefore the function is not one-to-one.
