The line goes through the points (4,-3) and (0,-2), so its gradient is (-2-(-3))/(0-4) = -1/4. The y-intercept is -2 because f(0)=-2. So the equation of the line is y = -1/4 x - 2.This can be represented by the linear function f(x) = (-1/4)x - 2.
The composite function ff is given by ff(x) = f(-1/4 x - 2) = (-1/4)((-1/4)x - 2) - 2 = x/16 - 3/2.
