The slope is 8. In an equation of a line, y =mx + b the m is the slope and the b is the y-intercept. In your equation, you have y = 8x -1
If we look at y = mx + b and y = 8x -b we can see the similarities
y = mx + b
y = 8x - 1
m = slope = 8
b = y-intercept = -1
Slope = 8