Explanation:
To solve a two-variable system of inequalities, we need to graph the solution set. The solution set is the overlapping region between the two inequalities.
Let's take an example of a two-variable system of inequalities:
3x + 2y ≤ 12
x - y > 1
To graph this system of inequalities, we will first graph each inequality separately.
For the first inequality, we will start by finding its intercepts:
When x = 0, 2y = 12, so y = 6.
When y = 0, 3x = 12, so x = 4.
Plotting these intercepts and drawing a line through them gives us the boundary line for the first inequality:
3x + 2y = 12
Next, we will shade one side of the line to indicate which half-plane satisfies the inequality. To determine which side to shade, we can choose a test point that is not on the line. The origin (0,0) is a convenient test point. Substituting (0,0) into the inequality gives us:
3(0) + 2(0) ≤ 12
0 ≤ 12
Since this is true, we shade the side of the line that contains the origin:
[insert image of shaded half-plane]
Now let's graph the second inequality:
For this inequality, we will again start by finding its intercepts:
When x = 0, -y > 1, so y < -1.
When y = 0, x > 1.
Plotting these intercepts and drawing a line through them gives us the boundary line for the second inequality:
x - y = 1
Note that this line is dashed because it is not part of the solution set (the inequality is strict).
Next, we will shade one side of the line to indicate which half-plane satisfies the inequality. To determine which side to shade, we can again choose a test point that is not on the line. The origin (0,0) is a convenient test point. Substituting (0,0) into the inequality gives us:
0 - 0 > 1
This is false, so we shade the other side of the line:
[insert image of shaded half-plane]
The solution set for the system of inequalities is the overlapping region between the two shaded half-planes:
[insert image of overlapping region]
So the solution set is 3x + 2y ≤ 12 and x - y > 1 .
In summary, to solve a two-variable system of inequalities, we need to graph each inequality separately and shade one side of each boundary line to indicate which half-plane satisfies the inequality. The solution set is the overlapping region between the shaded half-planes.