Consider a straight line drawn on the Cartesian plane.
(i) Define the terms "slope" and "y-intercept" with respect to the graph of a line.
(ii) Explain, with justification, how the slope of the line can be obtained from any two distinct visible points on its graph.
(iii) Describe, in logical order, the steps required to write the equation of the line in the form y=mx+c once its slope and y-intercept have been identified.