Table of contents

0. Review of Algebra4h 16m
1. Equations & Inequalities3h 18m
2. Graphs of Equations43m
3. Functions2h 17m
4. Polynomial Functions1h 44m
5. Rational Functions1h 23m
6. Exponential & Logarithmic Functions2h 28m
7. Systems of Equations & Matrices4h 6m
8. Conic Sections2h 23m
9. Sequences, Series, & Induction1h 19m
10. Combinatorics & Probability1h 45m

0. Review of Algebra

Algebraic Expressions

College Algebra

0. Review of Algebra

Algebraic Expressions

1:07 minutes

Problem 144

Textbook Question

Evaluate each expression for x = -4 and y = 2. |2x - 5y|

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Key Concepts

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

Absolute Value

The absolute value of a number is its distance from zero on the number line, regardless of direction. It is denoted by vertical bars, such as |x|, and is always non-negative. For example, |3| = 3 and |-3| = 3. Understanding absolute value is crucial for evaluating expressions that involve both positive and negative outcomes.

Substitution

Substitution is the process of replacing a variable in an expression with a specific value. In this case, we substitute x = -4 and y = 2 into the expression |2x - 5y|. This step is essential for simplifying the expression to a numerical value, allowing for further evaluation.

Linear Expressions

A linear expression is an algebraic expression in which each term is either a constant or the product of a constant and a single variable raised to the first power. The expression 2x - 5y is linear, and understanding how to manipulate and evaluate such expressions is fundamental in algebra. Evaluating linear expressions involves performing arithmetic operations according to the order of operations.