Chapter 8: Problem 36
Solve each double inequality. Graph the solution set and write it using interval notation. $$ 7<3 x-2<25 $$
Short Answer
Expert verified
Interval notation: (3, 9)
Step by step solution
01
Solve the Left Inequality
Start by solving the left part of the double inequality: \( 7 < 3x - 2 \). Add 2 to both sides to isolate the term with \( x \). This gives \( 9 < 3x \). Then, divide each side by 3 to solve for \( x \): \( 3 < x \).
02
Solve the Right Inequality
Next, solve the right part of the double inequality: \( 3x - 2 < 25 \). Add 2 to both sides to isolate the term with \( x \). This gives \( 3x < 27 \). Then, divide each side by 3 to solve for \( x \): \( x < 9 \).
03
Combine Inequalities and Write Interval Notation
Combine the results from Step 1 and Step 2 to write the solution as a single compound inequality: \( 3 < x < 9 \). In interval notation, this is written as \((3, 9)\).
04
Graph the Solution Set
To graph the solution set \((3, 9)\), draw a number line. Place an open circle on 3 and an open circle on 9. Shade the region between these two points to represent all numbers greater than 3 and less than 9, excluding 3 and 9 themselves.
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Graphing Inequalities
Graphing inequalities is a crucial skill in understanding how a range of values can satisfy an inequality condition. The process involves visualizing the set of possible solutions on a number line. Consider the double inequality from our exercise: \(3 < x < 9\). When graphing this:
- Draw a horizontal line representing the number line.
- Identify the critical values in the inequality - in this case, 3 and 9.
- Place open circles at these points. Open circles indicate that these end-values are not included in the solution set.
- Shade the region between the two circles to show all numbers greater than 3 and less than 9 are included.
Compound Inequalities
A compound inequality consists of two separate inequalities joined by either "and" or "or". The original exercise demonstrates a type of compound inequality known as a double inequality, where a single variable is sandwiched between two numbers, such as \(7 < 3x - 2 < 25\).
- "And" compound inequalities specify that both conditions must be true simultaneously. The solution set consists of values that satisfy both inequalities. In this case, that's between 3 and 9.
- "Or" compound inequalities would allow for solutions to satisfy either condition, leading to possibly disjoint sets of solutions.
Interval Notation
Interval notation is a concise way to express the set of all real numbers that satisfy an inequality. For our exercise, the solution to the double inequality \(3 < x < 9\) is expressed in interval notation as \((3, 9)\). Here's how interval notation works:
- Parentheses, \(( )\), indicate that an endpoint is not included in the interval. This is the case when the inequality is strict.
- Brackets, \([ ]\), indicate that an endpoint is included. You would use brackets if the inequality were non-strict, like \(\leq\).
- The lower bound value is written first, followed by the upper bound, separated by a comma.