#### Answer

The function is not a one-to-one function.

#### Work Step by Step

In order for the function to be one-to-one:
For each value of $x$, there must be a unique $y$ value paired with it and every element of the domain (D) must be paired with a unique element of the range (R).
We can see that for the value of $y=200$, there are two values of $x$; that is, $20$ and $25$
Therefore, the function is not a one-to-one function.