Answer
Nonlinear
Work Step by Step
We see that, the points in the first half have different slope than the points in the second half. This means that the slope is not constant.
Hence the relation is $\text{nonlinear}$.
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.