
Linear Inequalities
© Thomas O'Sullivan 1997
A line is a set of points that obey a certain condition.
e.g. 2x + 3y = 6 is "the set of points such that twice the first ordinate plus three times the second ordinate equals six". (3,12), (0,2), (1.5,1) etc. are all points on this line as they obey the fixed condition.
A "half plane" or a "side of a line" is also a set of points that obey a certain condition.
e.g. 2x + 3y ³ 6 is "the set of points such that twice the first ordinate plus three times the second ordinate is less than or equal to six". (2,1), (2,0), (1,1), (3, 1), (0,1) etc. are all points on this "side of the line" as they all obey the fixed condition.

