The slope-intercept form:
y = mx + b
m - slope
b - y-intercept
We have f(x) = -2x + 3. Therefore the slope is m = -2.
The formula of a slope:

We have the points from the table
(2, -8) and (4, -2). Substitute:

The positive difference between the slopes of f(x) and g(x):
3 - (-2) = 3 + 2 = 5
Answer: [B] 5