Enter the inequality you want to plot, set the dependent variable if desired and click on the Graph button. In previous chapters we solved equations with one unknown or variable. We will now study methods of solving systems of equations consisting of two equations and two variables. Upon completing this section you should be able to: Represent the Cartesian coordinate system and identify the origin and axes. Given an ordered pair, locate that point on the Cartesian coordinate system. Given a point on the Cartesian coordinate system, state the ordered pair associated with it.

## Which inequality is represented by this graph?

Note that this concept contains elements from two fields of mathematics, the line from geometry and the numbers from algebra. Rene Descartes devised a method of relating points on a plane to algebraic numbers. This scheme is called the Cartesian coordinate system for Descartes and is sometimes referred to as the rectangular coordinate system. Perpendicular means that two lines are at right angles to each other.

**Writing a Linear Inequality from a Graph**

The number lines are called axes. The horizontal line is the x-axis and the vertical is the y-axis. The zero point at which they are perpendicular is called the origin.

Axes is plural. Axis is singular. The arrows indicate the number lines extend indefinitely. Thus the plane extends indefinitely in all directions. The plane is divided into four parts called quadrants. These are numbered in a counterclockwise direction starting at the upper right. Points on the plane are designated by ordered pairs of numbers written in parentheses with a comma between them, such as 5,7. This is called an ordered pair because the order in which the numbers are written is important.

The ordered pair 5,7 is not the same as the ordered pair 7,5. Points are located on the plane in the following manner. First, start at the origin and count left or right the number of spaces designated by the first number of the ordered pair. Second, from the point on the x-axis given by the first number count up or down the number of spaces designated by the second number of the ordered pair. Ordered pairs are always written with x first and then y, x,y.

The numbers represented by x and y are called the coordinates of the point x,y. This is important. The first number of the ordered pair always refers to the horizontal direction and the second number always refers to the vertical direction.

Check each one to determine how they are located. What are the coordinates of the origin? Upon completing this section you should be able to: Find several ordered pairs that make a given linear equation true.

Locate these points on the Cartesian coordinate system. Draw a straight line through those points that represent the graph of this equation. A graph is a pictorial representation of numbered facts. There are many types of graphs, such as bar graphs, circular graphs, line graphs, and so on.

You can usually find examples of these graphs in the financial section of a newspaper. Graphs are used because a picture usually makes the number facts more easily understood.

In this section we will discuss the method of graphing an equation in two variables. In other words, we will sketch a picture of an equation in two variables.By Mary Jane Sterling.

Graphing linear functions and inequalities has a place in finite mathematics. A system of inequalities contains lots of points—each of them satisfying the statement of one or more inequalities. You can test different points to see which system is satisfied, often one at a time. Or you can look at a graph that gives you the overall view of the solutions. For example, you know that you can fit up to 16 ounces of a mixture of peanuts and almonds in your travel cup.

An almond weighs twice as much as a peanut. So, what can you put in the cup? You can do 10 ounces of peanuts and 3 ounces of almonds. That should fit. Also, you can do 4 ounces of peanuts and 6 ounces of almonds, with room to spare. Many different combinations either fill the cup or leave room for more.

To examine this situation in a more orderly fashion, let x represent the number of ounces of peanuts and y represent the number of ounces of almonds.

## Graphing Linear Inequalities

Remember that almonds weigh twice as much as peanuts. The values of x and y are never negative in a system with this requirement; they have to be positive or zero. This figure shows you the graph of the system. The next figure shows you the infinite number of choices. Now, starting with a completely new situation working toward a system of inequalities, the graphs used in this new system show the graphs of the separate inequalities and then intersection of those inequalities.

The graph of the system. When both inequalities are graphed on the same coordinate axes, you can see what points they share. For example, in the next figure, you see that the points are all common solutions of the two inequalities.

### Steps on How to Graph Linear Inequalities

They are all solutions of the system. She taught at Bradley University in Peoria, Illinois for more than 30 years, teaching algebra, business calculus, geometry, and finite mathematics. How to Graph Systems of Inequalities.

All the points in the solution are in the triangular area. Graph showing many ways to fill the cup.Forgot your password? Login Sign Up Free. Speak now. Quiz Maker All Products. Discuss Education Subject Math Algebra. Which inequality is represented by the graph below? Asked by RolandmelchorLast updated: Jul 13, Post Your Answer.

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Sign Up to save your work.Algebraic inequalities are sometimes referred to as literal inequalities. A linear inequality is same as a linear equation only that the equals sign is substituted by the inequality sign. The same steps and concepts used to graph linear equations are also applied to graph linear inequalities. The only difference between the two equations is that, a linear equation gives a line graph whereas a linear inequality shows the area of the coordinate plane that satisfies the inequality.

A linear inequality graph usually uses a borderline to divide the coordinate plane into two regions. One part of the region consists of all solutions to the inequality. Solving linear inequalities by graphing is really simple. Follow the above steps to draw the inequalities. Once drawn, the shaded area is a solution to that inequality. If there are more than one inequality then the common shaded area is a solution to inequalities. Search for:. How to Graph Linear Inequalities? The following are the steps for graphing an inequality: Given an inequality equation, make y the subject of the formula.

Plot and a line graph for these arbitrary values of x and y. How to Solve Linear Inequalities by Graphing? Subtract 2x from both sides of the equation.

Practice Questions 1. Check whether the point10 is within the solution set. Determine the slope of the border line. Is the point -5, -2 within the solution set?

Is the borderline drawn dashed or solid? Explain your answer. Determine whether the point 2, -2 is within the solution set. Which quadrant has no solutions to this inequality?We don't know the variable. By using this site, you consent to the use of cookies. You can refuse to use cookies by setting the necessary parameters in your browser. Mathematics Which inequality is represented by this graph? Answers: 1. Step-by-step explanation:.

The answer would be A. Other questions on the subject: Mathematics.

Mathematics, Using the sixth Excel worksheet, a Find P E. Why or why not? Why or why not. In a class 30 of students, 10 are female and 22 have an A in the class. There are 4 students who are female and have an A in the class.

What is the probability that a student chose Which equation represents a line that passes through 2, -1 and has a slope of 3? Write three nuclear equations to represent the nuclear decay sequence that begins with the alpha decay of U followed by a beta decay of the daughter nuclide and then another al In a study of crime, the FBI found that This result was based on a sample of 1, Estimate thStep 2: Change the inequality to equality symbol.

For now, you will deal with a line. Step 3: Graph the boundary line from step 2 in the XY- plane. The following are the three common methods that you can use to graph a line. In this step, you are constructing the boundary line that would separate or cut the XY- plane into two regions.

Step 5: Use this optional step to check or verify if you have correctly shaded the side of the boundary line. Step 1: The inequality is already in the form that we want. That is, the variable y is isolated on the left side of the inequality. Step 2: Change inequality to equality. Use the method that you prefer when graphing a line. The greater than symbol implies that we are going to shade the top area or region.

Now, we substitute and evaluate the coordinates of the test point with the original inequality. So where do we start? Below are the suggested steps that you can follow in order to do it right. We use cookies to give you the best experience on our website. Otherwise, check your browser settings to turn cookies off or discontinue using the site. Cookie Policy.The representation is clearer if you look at what the y -coordinates of these points have in common.

From the equation m will be the gradient and c will be the y -intercept. The gradient is then and the y -intercept is — 2. We shade below the line.

We shade above the line. Note: A question may require you to shade the wanted region or the unwanted region. If the question does not specify which region to shade, then state which region you are shading. While it may seem to be more intuitive to shade the wanted region here, shading the unwanted region is more useful in linear programming.

Rotate to landscape screen format on a mobile phone or small tablet to use the Mathway widget, a free math problem solver that answers your questions with step-by-step explanations.

We welcome your feedback, comments and questions about this site or page. Please submit your feedback or enquiries via our Feedback page. We also have a systems of inequalities calculator that can display the shaded region that satisfies all the given inequalities. We will revise the method for drawing a straight line. After drawing the line, we need to shade the unwanted region. You can use the free Mathway calculator and problem solver below to practice Algebra or other math topics.

Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.

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