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Ch. 1 - Equations and Inequalities
Lial - College Algebra 13th Edition
Lial13th EditionCollege AlgebraISBN: 9780136881063Not the one you use?Change textbook
Chapter 2, Problem 29

Solve each inequality. Give the solution set in interval notation. -5<5+2x<11

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1
Start by understanding that the inequality -5 < 5 + 2x < 11 is a compound inequality, meaning you need to solve both parts simultaneously.
First, isolate the middle expression by subtracting 5 from all three parts of the inequality: -5 - 5 < 5 + 2x - 5 < 11 - 5, which simplifies to -10 < 2x < 6.
Next, solve for x by dividing all parts of the inequality by 2 (since 2 is positive, the inequality signs remain the same): \(\frac{-10}{2}\) < \(\frac{2x}{2}\) < \(\frac{6}{2}\), which simplifies to -5 < x < 3.
Interpret the solution: x is greater than -5 and less than 3, so the solution set includes all real numbers between -5 and 3, not including -5 and 3 themselves.
Write the solution set in interval notation as ( -5, 3 ).

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Compound Inequalities

A compound inequality involves two inequalities joined together, often with 'and' or 'or'. In this problem, the inequality -5 < 5 + 2x < 11 means both conditions must be true simultaneously. Solving requires isolating the variable within the combined inequality.
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Solving Linear Inequalities

Solving linear inequalities involves performing algebraic operations to isolate the variable while maintaining the inequality's direction. When multiplying or dividing by a negative number, the inequality sign reverses. The goal is to find all values of x that satisfy the inequality.
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Interval Notation

Interval notation is a concise way to represent solution sets of inequalities using parentheses and brackets. Parentheses indicate values not included (open interval), while brackets indicate inclusion (closed interval). For example, (a, b) means all numbers between a and b, excluding endpoints.
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