Answer:
[tex]\frac{-9}{12}[/tex]
Step-by-step explanation:
First, we need to isolate y.
1. Subtract 12x from both sides.
-9y=-12x+135
2. Divide by -9 in order to isolate y.
[tex]y=\frac{12}{9} x-15[/tex]
3. Understand that perpendicular equations' slopes are opposite and reciprocal to the original equation. The slope of the original equation is [tex]\frac{12}{9}[/tex], so the reciprocal and opposite (flip and change the sign) slope would be [tex]\frac{-9}{12}[/tex].