Math Problem Statement

Solve the following: 1. \( \sqrt[3]{5x + x^2 - 8} = -2 \) 2. Find the domain and zeros of the function \( y = \frac{\sqrt{|x| - 1}}{x^2 - 3} \) 3. Solve the inequality \( \frac{x^7(x^2 + 4x + 4)}{x^2 - 3} \leq 0 \)

Solution

Let's solve the problems presented in the image one by one.


1. Solve the equation:

5x+x283=2\sqrt[3]{5x + x^2 - 8} = -2

Solution:

  • Start by cubing both sides to eliminate the cube root: 5x+x28=(2)35x + x^2 - 8 = (-2)^3 Simplifying the right side: 5x+x28=85x + x^2 - 8 = -8

  • Add 8 to both sides to cancel the constant: 5x+x2=05x + x^2 = 0

  • Factor the equation: x(5+x)=0x(5 + x) = 0

  • This gives two solutions: x=0orx=5x = 0 \quad \text{or} \quad x = -5

Solution set: x=0orx=5x = 0 \quad \text{or} \quad x = -5


2. Find the domain and zeros of the function:

y=x1x23y = \frac{\sqrt{|x| - 1}}{x^2 - 3}

Solution:

  • Domain:

    • The expression inside the square root must be non-negative: x10x1|x| - 1 \geq 0 \quad \Rightarrow \quad |x| \geq 1 This gives two intervals: x1orx1x \leq -1 \quad \text{or} \quad x \geq 1
    • The denominator cannot be zero: x230x±3x^2 - 3 \neq 0 \quad \Rightarrow \quad x \neq \pm\sqrt{3}
    • Therefore, the domain of the function is: (,3)(3,1][1,3)(3,)(-\infty, -\sqrt{3}) \cup (-\sqrt{3}, -1] \cup [1, \sqrt{3}) \cup (\sqrt{3}, \infty)
  • Zeros:

    • For the function to be zero, the numerator must be zero: x1=0x1=0x=1\sqrt{|x| - 1} = 0 \quad \Rightarrow \quad |x| - 1 = 0 \quad \Rightarrow \quad |x| = 1 Thus, x=±1x = \pm 1.

Zeros: x=1andx=1x = -1 \quad \text{and} \quad x = 1


3. Solve the inequality using the interval method:

x7(x2+4x+4)x230\frac{x^7(x^2 + 4x + 4)}{x^2 - 3} \leq 0

Solution:

  • Factor the quadratic in the numerator: x2+4x+4=(x+2)2x^2 + 4x + 4 = (x + 2)^2 So the inequality becomes: x7(x+2)2x230\frac{x^7(x + 2)^2}{x^2 - 3} \leq 0

  • Critical points occur where the expression equals zero or is undefined:

    • x7=0x=0x^7 = 0 \Rightarrow x = 0
    • (x+2)2=0x=2(x + 2)^2 = 0 \Rightarrow x = -2
    • x23=0x=±3x^2 - 3 = 0 \Rightarrow x = \pm\sqrt{3}
  • These critical points divide the real line into intervals. We need to test each interval to see where the expression is negative or zero: (,3),(3,2),(2,0),(0,3),(3,)(-\infty, -\sqrt{3}), (-\sqrt{3}, -2), (-2, 0), (0, \sqrt{3}), (\sqrt{3}, \infty)

    • Analyze the sign of the expression in each interval and consider the zeros.
  • Final solution: The inequality is satisfied in the following intervals: (,3)(2,0](0,3)(-\infty, -\sqrt{3}) \cup (-2, 0] \cup (0, \sqrt{3})


Would you like more details on any of these solutions?

Here are 5 related questions for practice:

  1. How would the equation change if the cube root in problem 1 were replaced with a square root?
  2. What is the range of the function in problem 2?
  3. How would the solution change in problem 3 if the inequality were strict <0< 0?
  4. Can you solve 5x+x283=3\sqrt[3]{5x + x^2 - 8} = 3?
  5. How would you find the maximum or minimum of the function in problem 2?

Tip: Always check the domain of a function before solving, especially if there are square roots or denominators.

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Math Problem Analysis

Mathematical Concepts

Cubic Equations
Inequalities
Function Domain and Zeros
Interval Method

Formulas

Cube root elimination: cube both sides
Function domain and zeros: Square root conditions and denominator restrictions
Factoring quadratic expressions: x^2 + 4x + 4 = (x + 2)^2

Theorems

Factoring Theorem
Properties of cube roots
Square root domain restrictions
Sign analysis in inequalities

Suitable Grade Level

Grades 10-12