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
4. Polynomial Functions
Quadratic Functions
Problem 7a
Textbook Question
Solve each problem. During the course of a year, the number of volunteers available to run a food bank each month is modeled by , where between the months of January and August. Here x is time in months, with x=1 representing January. From August to December, V(x) is modeled by . Find the number of volunteers in each of the following months.
January
Verified step by step guidance1
Identify the given piecewise function for the number of volunteers, \(V(x)\), where \(x\) represents the month number with \(x=1\) for January. For January, since \(x=1\) falls between January and August, use the first function: \(V(x) = 2x^2 - 32x + 150\).
Substitute \(x=1\) into the function \(V(x) = 2x^2 - 32x + 150\) to find the number of volunteers in January.
Calculate the value inside the function step-by-step: first compute \(x^2\), then multiply by 2, next multiply \(x\) by 32, and finally perform the addition and subtraction as indicated.
Write the expression after substitution as \(V(1) = 2(1)^2 - 32(1) + 150\) and simplify each term accordingly.
Combine all simplified terms to express the number of volunteers in January, which completes the evaluation for \(x=1\).
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Piecewise Functions
A piecewise function is defined by different expressions over different intervals of the domain. In this problem, V(x) has one formula from January to August and another from August to December. Understanding how to evaluate the correct expression based on the input value x is essential.
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Function Composition
Function Evaluation
Function evaluation involves substituting a given input value into the function's formula to find the output. Here, to find the number of volunteers in January (x=1), substitute x=1 into the appropriate formula and simplify to get V(1).
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Evaluating Composed Functions
Quadratic and Linear Functions
The function V(x) is quadratic (2x² - 32x + 150) for January to August and linear (31x - 226) for August to December. Recognizing the type of function helps in understanding its behavior and correctly performing calculations.
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Introduction to Quadratic Equations
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Related Practice
Textbook Question
In Exercises 5–8, the graph of a quadratic function is given. Write the function's equation, selecting from the following options.
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