An equation in the slope-intercept form is f(x) = mx + b, where m is the slope and b is the y-intercept.
Given:
slope = m = 5
The equation is f(x) = 5x + b
To find b, let's use the point (-2, -8), substituting x by -2 and f(x) by -8.

Answer:
The equation of the line is f(x) = 5x - 2.