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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 34b

Use the graph to evaluate each expression. See Example 3(a).
(ƒ-g)(-1)

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1
Understand that (ƒ - g)(-1) means you need to find the value of ƒ(-1) and g(-1) from the graph, then subtract g(-1) from ƒ(-1).
Locate the point where x = -1 on the x-axis and find the corresponding y-value on the red curve (ƒ(x)) to determine ƒ(-1).
Next, locate the point where x = -1 on the x-axis and find the corresponding y-value on the blue line (g(x)) to determine g(-1).
Write the expression for the difference: (ƒ - g)(-1) = ƒ(-1) - g(-1).
Substitute the values you found for ƒ(-1) and g(-1) into the expression and simplify to find the result.

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Key Concepts

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

Function Notation and Evaluation

Function notation, such as f(x) and g(x), represents the output of a function for a given input x. To evaluate a function at a specific value, substitute the input into the function and find the corresponding output on the graph or from the equation.
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Evaluating Composed Functions

Operations on Functions (Addition and Subtraction)

Operations like (f - g)(x) involve subtracting the output of g(x) from f(x) for the same input x. This means evaluating both functions at x and then subtracting their values to find the result.
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Adding & Subtracting Functions

Reading Values from a Graph

To evaluate functions from a graph, locate the input value on the x-axis, then find the corresponding y-values for each function by tracing vertically to the graph lines. These y-values represent the function outputs needed for calculations.
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Graphs & the Rectangular Coordinate System