The student forgot one negative sign in the numerator. $x=-3$, not $x=3$ as the student calculated.
Work Step by Step
$-b/2a = -(-6)/2*-1 = 6/-2 = -3$
You can help us out by revising, improving and updating this answer.Update this answer
After 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.