Answer
$(-2,-3)$ and $(6,-3)$.
Work Step by Step
Given center $(2,-3)$ and $a=4$ along a horizontal axis, we have the vertices as $(2\pm a,-3)$ or $(-2,-3)$ and $(6,-3)$.
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.