Answer
Negative.
Work Step by Step
Although the particle is speeding up, the velocity points to left (negative direction). It's becoming more negative ($\Delta$v $\lt$ 0).
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.