The primary idea behind the geometrical representation adopted in the
subsequent analysis, is to correspond every vector 
denoting the variables of a 2-var LP, to the point with co-ordinates
in a 2-dim (planar) Cartesian system. Under this
correspondence, the feasible region of a 2-var LP is depicted by the
set of points the coordinates of which satisfy the LP constraints and
the sign restrictions. Since all these constraints are expressed by
linear inequalities, to geometrically characterize the feasible
region, we must first characterize the set of points that constitute
the solution space of a linear inequality. Then, the LP feaslible
region will result from the intersection of the solution spaces
corresponding to each technological constraint and/or sign
restriction.