College Board · AP Precalculus

AP Precalculus: Polynomial and Rational Functions — Practice Questions & Answers

Unit 1 of AP Precalculus builds the foundation of function analysis: how polynomial and rational functions behave, where they cross zero, how fast they change, and how they transform. You will learn to read structure from a formula, predict end behavior, locate zeros and asymptotes, solve inequalities, and choose appropriate models from data.

178 practice questions available for this topic — here are 10 with full answers and explanations.

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Practice questions with answers

1 Multiple choice · Easy

For $f(x)=x^{2}$, what is the average rate of change on the interval $[1,3]$?

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WhyAverage rate of change is $\frac{f(3)-f(1)}{3-1}=\frac{9-1}{2}=4$.
2 Multiple choice · Easy

What is the degree of the polynomial $f(x)=3x^{4}-2x^{2}+x-7$?

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WhyThe degree is the highest exponent on the variable, which is $4$.
3 Multiple choice · Easy

Describe the end behavior of $f(x)=2x^{4}-5x+1$.

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WhyAn even degree with a positive leading coefficient rises on both ends: $f(x)\to\infty$ as $x\to\pm\infty$.
4 Multiple choice · Easy

The function $f(x)=x^{3}$ is best classified as:

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WhySince $f(-x)=(-x)^{3}=-x^{3}=-f(x)$, the function is odd.
5 Multiple choice · Easy

What is the leading term of $f(x)=5-3x^{2}+x^{5}$?

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WhyThe leading term is the term with the highest degree, which is $x^{5}$.
6 Fill in the blank · Easy

For $f(x)=2x+1$, the average rate of change on the interval $[0,4]$ is .

Answer: 2

Why$\frac{f(4)-f(0)}{4-0}=\frac{9-1}{4}=2$, which equals the slope of the line.
7 Multiple choice · Easy

Where is the vertical asymptote of $f(x)=\frac{1}{x-2}$?

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WhyThe denominator is zero at $x=2$ and the numerator is nonzero there, giving a vertical asymptote $x=2$.
8 Fill in the blank · Easy

The degree of the polynomial $f(x)=(x-1)^{2}(x+3)^{3}$ is .

Answer: 5

WhyAdd the multiplicities: $2+3=5$.
9 Multiple choice · Easy

At a real zero of even multiplicity, the graph of a polynomial:

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WhyAt an even-multiplicity zero the graph touches the x-axis and turns around without crossing.
10 Multiple choice · Medium

For $f(x)=x^{2}-3x$, what is the average rate of change on $[1,4]$?

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Why$f(4)=4$ and $f(1)=-2$, so $\frac{4-(-2)}{4-1}=\frac{6}{3}=2$.

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Key terms in Polynomial and Rational Functions

Function: A relation that assigns to each input exactly one output. It can be expressed as $f(x)$ where $x$ is the input.
Input Value: The independent variable supplied to a function, typically denoted $x$. It belongs to the domain.
Output Value: The dependent value produced by a function for a given input, typically denoted $y$ or $f(x)$.
Domain: The complete set of all permissible input values for a function. It excludes values that cause undefined outputs.
Range: The complete set of all output values a function can produce over its domain.
Independent Variable: The variable representing input, whose value is chosen freely, usually $x$.
Dependent Variable: The variable representing output, whose value depends on the input, usually $y$.
Increasing Function: A function whose output values rise as the input values increase over an interval.

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