You can put this solution on YOUR website!
The formula for the slope of line through two given points is
m(slope) = (y2-y1)/(x2-x1).
Using the values in your problem, the slope is
(-6-(-8))/(3-4)= (-6+8)/(-1) = 2/(-1) = -2
The formula for the slope of a line is sometimes described as the rise/run. With a negative slope, the line is decreasing (moving downward).
I hope that this helps.