Answer:
[tex]-\frac{1}{3}[/tex]
Step-by-step explanation:
The slope of a line perpendicular to a line is the negative reciprocal of the slope of the line given.
The equation of the line is:
[tex]3x-y=6[/tex]
[tex]y=3x-6[/tex]
The slope of this line is 3.
Thus the negative reciprocal would be [tex]-\frac{1}{3}[/tex]