First of all, lets get y on its own side of the equation.
[tex]-y=-2x+6\\y=2x-6\\[/tex]
This is slope intercept form, y=mx+b, where m is slope.
we can see that m=2, so the slope is 2 or [tex]\frac{2}{1}[/tex]
2x-y=6
m=-2/1
m=2
Hope this helped:)