Skip to main content
Ch. 3 - Polynomial and Rational Functions
Blitzer - College Algebra 8th Edition
Blitzer8th EditionCollege AlgebraISBN: 9780136970514Not the one you use?Change textbook
Chapter 4, Problem 79

In Exercises 57–80, follow the seven steps to graph each rational function. f(x)=(3x2+x−4)/(2x2−5x)

Verified step by step guidance
1
Identify the domain of the function by finding the values of x that make the denominator zero. Solve 2x^2 - 5x = 0 to find these values, since the function is undefined there.
Find the intercepts: For the y-intercept, evaluate f(0) if it is in the domain. For the x-intercepts, set the numerator equal to zero and solve 3x^2 + x - 4 = 0 to find the values of x where f(x) = 0.
Determine any vertical asymptotes by using the values of x that make the denominator zero (from step 1), provided these values do not also make the numerator zero (which would indicate a hole instead).
Find the horizontal or oblique (slant) asymptote by comparing the degrees of the numerator and denominator polynomials. Since both are degree 2, divide the leading coefficients to find the horizontal asymptote.
Analyze the behavior of the function near the vertical asymptotes and at the ends of the domain by testing values of x in each interval determined by the vertical asymptotes, and use this information to sketch the graph.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
17m
Was this helpful?

Key Concepts

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

Rational Functions

A rational function is a ratio of two polynomials, expressed as f(x) = P(x)/Q(x). Understanding its domain, where the denominator Q(x) ≠ 0, is essential to avoid undefined values and to analyze the function's behavior.
Recommended video:
6:04
Intro to Rational Functions

Asymptotes

Asymptotes are lines that the graph of a function approaches but never touches. Vertical asymptotes occur where the denominator is zero, and horizontal or oblique asymptotes describe end behavior as x approaches infinity or negative infinity.
Recommended video:
6:24
Introduction to Asymptotes

Graphing Steps for Rational Functions

Graphing rational functions involves identifying domain restrictions, intercepts, asymptotes, and behavior near asymptotes, then plotting points to sketch the curve. Following a systematic approach ensures an accurate and complete graph.
Recommended video:
8:19
How to Graph Rational Functions