The graph of a linear function is a straight line. f(0) = -5 means that (0,-5) is a point on the line. Similarly, (-5,-6) is also a point on the line. [ Slope of line = m = [-6-(-5)]/[-5-0] = -1/(-5) = 1/5 Using the point-slope form, an equation of the line is: y - (-5) = (1/5)(x - 0) So, y = (1/5)x - 5 ]