You can also graph the linear equations or inequalities on your graphing calculator to find solutions.

Let's say that you are asked to determine if (8, -2) is a solution to y = 2 5 x + 4.

Step 1:

Enter the equation in

Step 2:

Look at the graph for this equation by pressing (You may need to set your window.)

Step 3:

Use the feature by pressing and then typing 8 and pressing

It's easy to see that when x = 8, y = 7.2 and so (8, -2) is NOT a solution to the equation since the point is not on the graph.

Let's look at a linear inequality next.

Is (-1, -6) a solution for y ≤ 3x − 2?

Step 1:

Enter the equation in

Step 2:

Look at the graph for this equation by pressing (You may need to set your window.)

Remember that we are looking for points where y is less than or equal to. So we are looking for points that not only include the points on the line but are also below the line.

The solutions for y ≤ 3x − 2 are located on the line itself and the shaded portion of the graph.

Is (-1, -6) in this shaded region? YES, so it is a solution.

Use the Graph feature on your calculator and determine if the given ordered pair is a solution to each linear equation or inequality.

1. Is (-1, -6) a solution for y < 2 3 x − 1?
2. Is (-8, 2.4) a solution for y = - 1 2 x − 1.6?
3. Is (-2, 5.6) a solution for 2yx ≥ 2?