Two different straight lines L1 and L2 are plotted on the same coordinate grid.
• L1 passes through the points P(−4,1) and Q(2,7).
• L2 passes through the points R(−4,5) and S(4,−3).
(i) Obtain the equation of each line in the form ax+by+c=0 using only the given points.
(ii) Solve the pair of equations from part (i) to find the coordinates of the point of intersection of L1 and L2.
(iii) Determine, with reason, whether the origin (0,0) lies between the two lines or on the same side of both lines.