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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 33a

Use the graph to evaluate each expression. See Example 3(a).
(ƒ+g)(2)
Graph showing two functions: a blue parabola y = f(x) opening upward and a red line y = g(x) with positive slope.

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Identify the value of x for which you need to evaluate the expression. Here, it is x = 2.
Locate x = 2 on the horizontal axis (x-axis) of the graph.
Find the corresponding y-values for both functions f(x) and g(x) at x = 2 by looking at the points on the orange curve (f) and the blue line (g).
Write down the values: f(2) and g(2) from the graph.
Add the two values together to find (f + g)(2) using the formula: \[(f + g)(2) = f(2) + g(2)\].

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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. Evaluating a function at a specific value means finding the corresponding y-value on the graph or from the function's equation. For example, f(2) is the y-value of function f when x = 2.
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Evaluating Composed Functions

Function Addition (ƒ + g)(x)

The sum of two functions, (ƒ + g)(x), is found by adding their outputs for the same input x. This means (ƒ + g)(2) = f(2) + g(2). Understanding this concept allows you to combine values from two different functions at a specific point.
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Adding & Subtracting Functions Example 1

Reading Values from a Graph

To evaluate functions using a graph, locate the input value on the x-axis, then find the corresponding y-values on each function's curve. Accurate reading of these points is essential for correctly evaluating expressions like (ƒ + g)(2) by summing the y-values of f and g at x = 2.
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Graphs & the Rectangular Coordinate System