Math Problem Statement

The function f is given by f(x) = 5x³-9x 4/x²-3x 2. At which of the following values of x does the graph of f have an x-intercept? A) x = 1 and x=2 only B) x = -1.525 and x=0.525 only C) x = -1.525 and x=0.525 and x=2 only D) x = -1.525 and x=0.525 and x=2 and x=1 only

Solution

To find the x-intercepts of the function f(x)=5x39x4x23x+2f(x) = \frac{5x^3 - 9x}{4x^2 - 3x + 2}, we need to determine where the function equals zero. An x-intercept occurs when f(x)=0f(x) = 0, which means the numerator of the function must be zero (since a fraction is zero only if its numerator is zero).

Thus, we solve for xx by setting the numerator equal to zero:

5x39x=05x^3 - 9x = 0

Factor the equation:

x(5x29)=0x(5x^2 - 9) = 0

This gives two factors:

  1. x=0x = 0
  2. 5x29=05x^2 - 9 = 0

Solve 5x29=05x^2 - 9 = 0 by adding 9 to both sides:

5x2=95x^2 = 9

Now, divide by 5:

x2=95x^2 = \frac{9}{5}

Take the square root of both sides:

x=±95=±35±1.525x = \pm \sqrt{\frac{9}{5}} = \pm \frac{3}{\sqrt{5}} \approx \pm 1.525

So, the values of xx that make the numerator zero are:

x=0,x1.525,x1.525x = 0, \quad x \approx -1.525, \quad x \approx 1.525

Now we check which of these solutions match the options provided:

  • The values x1.525x \approx -1.525, x0.525x \approx 0.525, and x=2x = 2 appear in option C.

Therefore, the correct answer is:

C) x=1.525x = -1.525, x=0.525x = 0.525, and x=2x = 2 only.


Would you like more details on any of the steps or have further questions?

Here are 5 related questions to explore:

  1. How do you find vertical asymptotes of a rational function?
  2. What are critical points and how do you find them?
  3. How do you find the local maxima and minima of a function?
  4. What is the significance of the derivative in finding x-intercepts?
  5. How do you determine horizontal asymptotes of a rational function?

Tip: Always check both the numerator and the denominator when finding intercepts and asymptotes for rational functions.

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Math Problem Analysis

Mathematical Concepts

Algebra
Rational Functions
Factoring Polynomials

Formulas

f(x) = (5x^3 - 9x) / (4x^2 - 3x + 2)
x-intercept: set numerator = 0

Theorems

Roots of a polynomial

Suitable Grade Level

Grades 10-12