Linear Inequalities: Error in book?

In summary, linear inequalities are mathematical expressions that compare two values using <, >, ≤, or ≥ symbols. They differ from linear equations in that they can have multiple solutions. To graph a linear inequality, solve for y and plot the y-intercept and additional points using the slope. The most common error when working with linear inequalities is forgetting to reverse the inequality symbol when multiplying or dividing by a negative number. To solve a system of linear inequalities, graph each inequality separately and find the overlapping region or solve algebraically.
  • #1
Holocene
237
0
Give the interval notation for the inequality: [tex]\displaystyle{x\leq -2[/tex]

My answer is: [tex]\displaystyle{(-\infty, -2]}[/tex]

Book answer is: [tex]\displaystyle{(\infty, -2]}[/tex]

?
 
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  • #2
You're right. Looks like a typo in the book.
 
  • #3
mathman said:
You're right. Looks like a typo in the book.


Thanks. This book is absolutely riddled with errors of this type; enough to make you often doubt yourself after successfully completing some problems.

I hope the editor doesn't have any competition...:rolleyes:
 
  • #4
When you read stuff like that you should know that it has to be a typo, because you know that it cannot make sense.
 

Related to Linear Inequalities: Error in book?

1. What are linear inequalities?

Linear inequalities are mathematical expressions that compare two values using the symbols <, >, ≤, or ≥. They represent a range of possible values that satisfy the inequality statement.

2. What is the difference between a linear equation and a linear inequality?

A linear equation is an expression that sets two values equal to each other, while a linear inequality compares two values and shows the relationship between them. Inequalities can have multiple solutions, while equations only have one solution.

3. How do you graph a linear inequality?

To graph a linear inequality, first solve for y to put the expression in slope-intercept form. Then, plot the y-intercept and use the slope to plot additional points. Finally, shade the area above or below the line, depending on the inequality symbol.

4. How do you solve a system of linear inequalities?

To solve a system of linear inequalities, graph each inequality separately and find the overlapping region. The overlapping region represents the solutions that satisfy all of the inequalities in the system. This can also be done algebraically by solving each inequality for y and then finding the common solution set.

5. What is the most common error made when working with linear inequalities?

The most common error made when working with linear inequalities is forgetting to reverse the inequality symbol when multiplying or dividing by a negative number. This is because multiplying or dividing by a negative number changes the direction of the inequality. It is important to always double check the direction of the inequality after performing any operations.

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