Math Problem Statement

Solve the following inequalities: 1) (x^2 - 10x + 9)(4x + 1)^2 > 0 2) (x^2 - 10x + 9)(4x + 1)^2 ≤ 0 3) (x^2 - 6x + 8)(x^2 - 4) ≤ 0

Solution

The image contains three inequalities that need to be solved. Let's go through them one by one:

1. (x210x+9)(4x+1)2>0(x^2 - 10x + 9)(4x + 1)^2 > 0

Here, we need to solve the inequality: (x210x+9)(4x+1)2>0(x^2 - 10x + 9)(4x + 1)^2 > 0

  1. Factorize the quadratic expression x210x+9x^2 - 10x + 9: x210x+9=(x9)(x1)x^2 - 10x + 9 = (x - 9)(x - 1) So the inequality becomes: (x9)(x1)(4x+1)2>0(x - 9)(x - 1)(4x + 1)^2 > 0

  2. The term (4x+1)2(4x + 1)^2 is always non-negative (since a square is always 0\geq 0). It will equal 0 only when x=14x = -\frac{1}{4}. So, we just need to find where (x9)(x1)(x - 9)(x - 1) is positive.

  3. Solve (x9)(x1)>0(x - 9)(x - 1) > 0 using a sign chart:

    • The roots are x=9x = 9 and x=1x = 1, which divide the number line into intervals: (,1)(-\infty, 1), (1,9)(1, 9), and (9,)(9, \infty).
    • Test points from each interval:
      • For x<1x < 1, both factors are negative, so the product is positive.
      • For 1<x<91 < x < 9, one factor is negative and one is positive, so the product is negative.
      • For x>9x > 9, both factors are positive, so the product is positive.
  4. Since (4x+1)2>0(4x + 1)^2 > 0 for all x14x \neq -\frac{1}{4}, the solution to the inequality is: (,1)(9,)(-\infty, 1) \cup (9, \infty) excluding x=14x = -\frac{1}{4}.


2. (x210x+9)(4x+1)20(x^2 - 10x + 9)(4x + 1)^2 \leq 0

This inequality is similar to the first, except we now have 0\leq 0.

  1. Factorize the quadratic again: (x9)(x1)(4x+1)20(x - 9)(x - 1)(4x + 1)^2 \leq 0.

  2. As (4x+1)2(4x + 1)^2 is non-negative and only zero when x=14x = -\frac{1}{4}, we focus on (x9)(x1)(x - 9)(x - 1):

    • (x9)(x1)=0(x - 9)(x - 1) = 0 when x=1x = 1 or x=9x = 9.
    • The quadratic product (x9)(x1)(x - 9)(x - 1) is negative between 11 and 99.
  3. The solution will include the points where the product equals zero (x=1x = 1 or x=9x = 9) and the interval where the product is negative. Therefore, the solution is: [1,9][1, 9]


3. (x26x+8)(x24)0(x^2 - 6x + 8)(x^2 - 4) \leq 0

Here, we need to solve: (x26x+8)(x24)0(x^2 - 6x + 8)(x^2 - 4) \leq 0

  1. Factorize each quadratic:

    • x26x+8=(x4)(x2)x^2 - 6x + 8 = (x - 4)(x - 2)
    • x24=(x2)(x+2)x^2 - 4 = (x - 2)(x + 2)

    The inequality becomes: (x4)(x2)(x+2)(x2)0(x - 4)(x - 2)(x + 2)(x - 2) \leq 0 or, simplified: (x4)(x2)2(x+2)0(x - 4)(x - 2)^2(x + 2) \leq 0

  2. The term (x2)2(x - 2)^2 is always non-negative and equals zero when x=2x = 2.

  3. Analyze the sign of the product (x4)(x+2)(x - 4)(x + 2) using a sign chart:

    • The roots are x=2x = -2 and x=4x = 4, dividing the number line into intervals: (,2)(-\infty, -2), (2,4)(-2, 4), and (4,)(4, \infty).
    • Test points in each interval:
      • For x<2x < -2, both factors are negative, so the product is positive.
      • For 2<x<4-2 < x < 4, one factor is negative and the other positive, so the product is negative.
      • For x>4x > 4, both factors are positive, so the product is positive.
  4. The solution is where the product is zero or negative. The solution is: [2,4][-2, 4]


Summary of Solutions:

  1. (,1)(9,)(- \infty, 1) \cup (9, \infty), excluding x=14x = -\frac{1}{4}.
  2. [1,9][1, 9]
  3. [2,4][-2, 4]

Would you like more details on any specific steps or clarifications?

Related Questions:

  1. How do we factor quadratic expressions efficiently?
  2. What is the importance of a sign chart in solving inequalities?
  3. Why does (4x+1)20(4x + 1)^2 \geq 0 for all real xx?
  4. How do we solve inequalities involving higher powers or more complex expressions?
  5. What are the key differences between strict (>>) and non-strict (\geq) inequalities?

Tip: Always test values between roots to understand how the sign of an expression changes across different intervals.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Inequalities
Factorization

Formulas

Quadratic equation formula: ax^2 + bx + c = 0
Factoring quadratic expressions
Sign chart for inequalities

Theorems

Quadratic factorization
Properties of inequalities

Suitable Grade Level

Grades 9-11