To solve a system of first degree inequalities graphically, we must:
draw on the same plane the graph of each inequality;
determine the region corresponding to the intersection of the two semiplanes.
Example: Give the graphic resolution of the system:
Solution:
Tracing the Straight -x + y = 4 and 3x + 2y = 6.
Table -x + y = 4
x | y | (x, y) |
0 | 4 | (0, 4) |
-4 | 0 | (-4, 0) |
Table 3x + 2y = 6
x | y | (x, y) |
0 | 3 | (0, 3) |
1 | 3/2 | (1, 3/2) |
Graphic: