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Ch. 2 - Graphs and Functions
Lial - College Algebra 13th Edition
Lial13th EditionCollege AlgebraISBN: 9780136881063Not the one you use?Change textbook
Chapter 3, Problem 6

To answer each question, refer to the following basic graphs. Which one is the graph of ƒ(x)=|x|? What is the function value when x=1.5?
Nine coordinate plane graphs labeled A to I showing various functions, including linear, quadratic, step, and absolute value shapes.

Verified step by step guidance
1
Recognize that the function ƒ(x) = |x| represents the absolute value of x, which means the output is always non-negative regardless of whether x is positive or negative.
Understand the shape of the graph of ƒ(x) = |x|: it forms a 'V' shape with its vertex at the origin (0,0), where the graph decreases linearly for x < 0 and increases linearly for x > 0.
Identify the graph among the given options that has this characteristic 'V' shape with the vertex at the origin, confirming it is the graph of ƒ(x) = |x|.
To find the function value when x = 1.5, substitute 1.5 into the function: ƒ(1.5) = |1.5|.
Since the absolute value of a positive number is the number itself, the function value at x = 1.5 is simply 1.5.

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Key Concepts

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

Absolute Value Function

The absolute value function, denoted as ƒ(x) = |x|, outputs the non-negative value of x. It transforms any negative input into its positive counterpart, making the graph V-shaped with a vertex at the origin (0,0). Understanding this function is key to identifying its graph and evaluating values.
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Graph Interpretation

Graph interpretation involves recognizing the shape and key features of a function's graph. For ƒ(x) = |x|, the graph consists of two linear pieces joined at the origin, sloping upward on both sides. Identifying this shape helps distinguish it from other basic graphs.
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Function Evaluation

Function evaluation means substituting a specific input value into the function to find the output. For ƒ(x) = |x|, evaluating at x = 1.5 involves calculating the absolute value of 1.5, which is 1.5. This process confirms the function's behavior at given points.
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