Math Problem Statement

Find the x-intercepts and y-intercepts of the given rational functions: 1. f(x) = (x - 8) / (x + 2) 2. f(x) = (x^2 - 10x + 25) / (x + 5) 3. f(x) = (x^2 + 9) / (x^2 - 1)

Solution

Let's analyze the image you uploaded, which contains three rational functions. The task is to find the xx-intercepts and yy-intercepts for each function.

Function 1: f(x)=x8x+2f(x) = \frac{x - 8}{x + 2}

  • xx-intercept: Set f(x)=0f(x) = 0: x8x+2=0\frac{x - 8}{x + 2} = 0 This implies that the numerator must be zero: x8=0x=8x - 8 = 0 \quad \Rightarrow \quad x = 8 So, the xx-intercept is (8,0)(8, 0).

  • yy-intercept: Set x=0x = 0: f(0)=080+2=82=4f(0) = \frac{0 - 8}{0 + 2} = \frac{-8}{2} = -4 So, the yy-intercept is (0,4)(0, -4).

Function 2: f(x)=x210x+25x+5f(x) = \frac{x^2 - 10x + 25}{x + 5}

  • xx-intercept: Set f(x)=0f(x) = 0: x210x+25x+5=0\frac{x^2 - 10x + 25}{x + 5} = 0 The numerator must be zero: x210x+25=(x5)2=0x=5x^2 - 10x + 25 = (x - 5)^2 = 0 \quad \Rightarrow \quad x = 5 So, the xx-intercept is (5,0)(5, 0).

  • yy-intercept: Set x=0x = 0: f(0)=0210(0)+250+5=255=5f(0) = \frac{0^2 - 10(0) + 25}{0 + 5} = \frac{25}{5} = 5 So, the yy-intercept is (0,5)(0, 5).

Function 3: f(x)=x2+9x21f(x) = \frac{x^2 + 9}{x^2 - 1}

  • xx-intercept: Set f(x)=0f(x) = 0: x2+9x21=0\frac{x^2 + 9}{x^2 - 1} = 0 Since x2+9x^2 + 9 is always positive for all real numbers xx, it can never be zero. Therefore, there are no xx-intercepts.

  • yy-intercept: Set x=0x = 0: f(0)=02+9021=91=9f(0) = \frac{0^2 + 9}{0^2 - 1} = \frac{9}{-1} = -9 So, the yy-intercept is (0,9)(0, -9).

Summary:

  1. f(x)=x8x+2f(x) = \frac{x - 8}{x + 2}:

    • xx-intercept: (8,0)(8, 0)
    • yy-intercept: (0,4)(0, -4)
  2. f(x)=x210x+25x+5f(x) = \frac{x^2 - 10x + 25}{x + 5}:

    • xx-intercept: (5,0)(5, 0)
    • yy-intercept: (0,5)(0, 5)
  3. f(x)=x2+9x21f(x) = \frac{x^2 + 9}{x^2 - 1}:

    • xx-intercept: None
    • yy-intercept: (0,9)(0, -9)

Would you like more details on any of these steps?

Here are some follow-up questions:

  1. What happens to the function's graph near points where the denominator is zero?
  2. How do we find vertical asymptotes of a rational function?
  3. What is the behavior of f(x)f(x) as xx approaches infinity for each function?
  4. How would the intercepts change if the functions were altered slightly?
  5. Can rational functions have slant asymptotes?

Tip: Remember, for rational functions, an xx-intercept occurs when the numerator equals zero, and the yy-intercept is found by substituting x=0x = 0 into the function.

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Math Problem Analysis

Mathematical Concepts

Algebra
Rational Functions
Intercepts

Formulas

x-intercept: Set f(x) = 0 and solve for x
y-intercept: Set x = 0 and solve for f(0)

Theorems

Zero Product Property

Suitable Grade Level

Grades 10-12