Consider the straight line y=5−2x.
(i) State the algebraic condition that an ordered pair (p,q) must satisfy in order to lie on this line.
(ii) Verify, with complete working, whether the points A(1,3), B(2,1) and C(−1,7) satisfy the condition you stated in part (i).
(iii) From the results of part (ii), identify the points (if any) that lie on the line and calculate the distance between every pair of such points.