Math Problem Statement

Analyze the properties of rational functions based on given equations, focusing on horizontal intercepts, vertical intercepts, vertical asymptotes, horizontal asymptotes, and domain.

Solution

Let’s solve the problems step by step for each given function:


Problem 1: g(x)=3x6x2+x6g(x) = \frac{3x - 6}{x^2 + x - 6}

Step 1: Horizontal intercepts (set numerator = 0)

  • The numerator is 3x63x - 6.
  • Solve 3x6=03x - 6 = 0: x=2x = 2
  • Horizontal intercept: (2,0)(2, 0)

Step 2: Vertical intercept (evaluate g(0)g(0))

  • Substitute x=0x = 0 into g(x)g(x): g(0)=3(0)602+06=66=1g(0) = \frac{3(0) - 6}{0^2 + 0 - 6} = \frac{-6}{-6} = 1
  • Vertical intercept: (0,1)(0, 1)

Step 3: Vertical asymptotes (set denominator = 0)

  • The denominator is x2+x6x^2 + x - 6. Factorize: x2+x6=(x+3)(x2)x^2 + x - 6 = (x + 3)(x - 2)
  • Solve x+3=0x + 3 = 0 and x2=0x - 2 = 0: x=3,x=2x = -3, \quad x = 2
  • Since x=2x = 2 is canceled as it is a root of both numerator and denominator, the vertical asymptote is: x=3x = -3

Step 4: Horizontal asymptote (compare degrees of numerator and denominator)

  • Degree of numerator = 1, degree of denominator = 2.
  • Since the numerator's degree is less than the denominator's degree, the horizontal asymptote is: y=0y = 0

Step 5: Domain

  • The denominator is undefined at x=3x = -3 and x=2x = 2.
  • Domain: x(,3)(3,2)(2,)x \in (-\infty, -3) \cup (-3, 2) \cup (2, \infty)

Problem 2: f(x)=2x22x12x2+3x18f(x) = \frac{2x^2 - 2x - 12}{x^2 + 3x - 18}

Step 1: Horizontal intercepts (set numerator = 0)

  • The numerator is 2x22x122x^2 - 2x - 12. Factorize: 2x22x12=2(x2x6)=2(x3)(x+2)2x^2 - 2x - 12 = 2(x^2 - x - 6) = 2(x - 3)(x + 2)
  • Solve (x3)(x+2)=0(x - 3)(x + 2) = 0: x=3,x=2x = 3, \quad x = -2
  • Horizontal intercepts: (3,0)(3, 0) and (2,0)(-2, 0)

Step 2: Vertical intercept (evaluate f(0)f(0))

  • Substitute x=0x = 0 into f(x)f(x): f(0)=2(0)22(0)12(0)2+3(0)18=1218=23f(0) = \frac{2(0)^2 - 2(0) - 12}{(0)^2 + 3(0) - 18} = \frac{-12}{-18} = \frac{2}{3}
  • Vertical intercept: (0,23)(0, \frac{2}{3})

Step 3: Vertical asymptotes (set denominator = 0)

  • The denominator is x2+3x18x^2 + 3x - 18. Factorize: x2+3x18=(x+6)(x3)x^2 + 3x - 18 = (x + 6)(x - 3)
  • Solve x+6=0x + 6 = 0 and x3=0x - 3 = 0: x=6,x=3x = -6, \quad x = 3
  • Vertical asymptotes: x=6x = -6, x=3x = 3

Step 4: Horizontal asymptote (compare degrees of numerator and denominator)

  • Degree of numerator = 2, degree of denominator = 2.
  • Since the degrees are the same, divide the leading coefficients: y=leading coefficient of numeratorleading coefficient of denominator=21=2y = \frac{\text{leading coefficient of numerator}}{\text{leading coefficient of denominator}} = \frac{2}{1} = 2
  • Horizontal asymptote: y=2y = 2

Step 5: Domain

  • The denominator is undefined at x=6x = -6 and x=3x = 3.
  • Domain: x(,6)(6,3)(3,)x \in (-\infty, -6) \cup (-6, 3) \cup (3, \infty)

Would you like a detailed breakdown of any specific part? Here are 5 related questions:

  1. How are horizontal asymptotes determined for rational functions?
  2. What is the process of identifying vertical asymptotes in more complex functions?
  3. Can you explain why the horizontal intercepts occur at numerator roots?
  4. How does the degree of the polynomial affect the behavior of a rational function?
  5. Would you like additional practice problems with rational functions?

Tip: Always check for removable discontinuities (holes) when a factor is shared between numerator and denominator!

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Math Problem Analysis

Mathematical Concepts

Rational Functions
Intercepts
Asymptotes
Domain of Functions

Formulas

For horizontal intercepts, set the numerator equal to zero.
For vertical intercepts, evaluate the function at x = 0.
For vertical asymptotes, set the denominator equal to zero.
Horizontal asymptotes depend on the degree of the numerator and denominator.

Theorems

Properties of rational functions
Relationship between numerator and denominator degrees for asymptotes

Suitable Grade Level

Grades 10-12