Okay, here we have this:
Considering that the slope of a line with the form Ax+By=C is equal to -A/B, we obtain the following:
m=-6/-5
m=6/5=1.2
Finally we obtain that the slope is 6/5 or 1.2.
Let's solve the exercise in another way, solving for "y", and the coefficient that we obtain from x will be our slope:
6x-5y=20
-5y=-6x+20
y=(-6x+20)/-5
y=-6x/-5-4
y=6/5x-4
Here we can see that the slope is 6/5.