Use the vertical line test to identify graphs in which y is a function of x.
Table of contents
- 0. Review of Algebra4h 18m
- 1. Equations & Inequalities3h 18m
- 2. Graphs of Equations1h 43m
- 3. Functions2h 17m
- 4. Polynomial Functions1h 44m
- 5. Rational Functions1h 23m
- 6. Exponential & Logarithmic Functions2h 28m
- 7. Systems of Equations & Matrices4h 5m
- 8. Conic Sections2h 23m
- 9. Sequences, Series, & Induction1h 22m
- 10. Combinatorics & Probability1h 45m
2. Graphs of Equations
Graphs and Coordinates
Problem 76
Textbook Question
Use the graph of g to solve Exercises 71–76.

For what value of x is g(x) = -1?
Verified step by step guidance1
Identify the value of \(y\) for which you want to find the corresponding \(x\) value. Here, we want to find \(x\) such that \(g(x) = -1\).
Look at the graph and locate the horizontal line where \(y = -1\) on the vertical axis.
Find the points on the graph where the function \(g(x)\) intersects the line \(y = -1\). These points represent the \(x\) values where \(g(x) = -1\).
Read the \(x\)-coordinate(s) of the intersection point(s) from the graph. This \(x\)-coordinate is the solution to \(g(x) = -1\).
If there are multiple intersection points, list all corresponding \(x\) values as solutions.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Function and Function Notation
A function relates each input (x) to exactly one output (y or f(x)). Function notation, like f(x), represents the output value corresponding to the input x. Understanding this helps interpret graphs and solve for specific function values.
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Function Composition
Reading a Graph to Find Function Values
To find where a function equals a certain value, locate the y-value on the vertical axis and identify the corresponding x-values on the graph. Points where the graph crosses or touches the horizontal line y = desired value give the solution.
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Finding the Domain and Range of a Graph
Interpreting Points and Coordinates on a Graph
Each point on a graph is an ordered pair (x, y) showing input and output values. Recognizing these points allows you to determine exact values of the function at specific inputs, which is essential for solving equations like f(x) = -1.
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Graphs and Coordinates - Example
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