Answer
9
Work Step by Step
$\frac{-12-(-3)}{-10-(-9)}=\frac{-12+3}{-10+9}=\frac{-9}{-1}=9$
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.