Math Problem Statement

-4x-32/x^2-12x+36 × x^2-9x+18/3x+24 What is the product in lowest terms? What values of [x] must we exclude from the domains of the expressions? Choose all answers that apply: Choose all answers that apply: (Choice A) [x=-8] A [x=-8] (Choice B) [x=0] B [x=0] (Choice C) [x=3] C [x=3] (Choice D) [x=6] D [x=6]

Solution

We are tasked with simplifying the given expression and identifying the excluded values of xx that make any denominator equal to zero. Let's break it down.

Expression:

4x32x212x+36×x29x+183x+24\frac{-4x - 32}{x^2 - 12x + 36} \times \frac{x^2 - 9x + 18}{3x + 24}

Step 1: Factor each part of the expression.

Factor the denominators and numerators.

  1. Factor x212x+36x^2 - 12x + 36:

This is a quadratic trinomial that factors as:

x212x+36=(x6)2x^2 - 12x + 36 = (x - 6)^2

  1. Factor 3x+243x + 24:

This is a linear expression that can be factored by taking out the greatest common factor (GCF):

3x+24=3(x+8)3x + 24 = 3(x + 8)

  1. Factor x29x+18x^2 - 9x + 18:

This is a quadratic trinomial that factors as:

x29x+18=(x6)(x3)x^2 - 9x + 18 = (x - 6)(x - 3)

  1. Factor 4x32-4x - 32:

We can factor out 4-4 from this expression:

4x32=4(x+8)-4x - 32 = -4(x + 8)

Step 2: Rewrite the expression with the factors:

4(x+8)(x6)2×(x6)(x3)3(x+8)\frac{-4(x + 8)}{(x - 6)^2} \times \frac{(x - 6)(x - 3)}{3(x + 8)}

Step 3: Simplify the expression.

Now we can cancel common factors:

  • x+8x + 8 in the numerator and denominator cancels out.
  • x6x - 6 in the numerator and denominator cancels out one of the (x6)(x - 6)'s in the denominator.

The simplified expression becomes:

4(x3)3(x6)\frac{-4(x - 3)}{3(x - 6)}

Step 4: Identify excluded values.

We exclude any xx-values that make the original denominators equal to zero.

  1. From x212x+36=(x6)2x^2 - 12x + 36 = (x - 6)^2:
    x6=0x - 6 = 0 implies x=6x = 6.

  2. From 3x+24=3(x+8)3x + 24 = 3(x + 8):
    x+8=0x + 8 = 0 implies x=8x = -8.

Thus, the values that must be excluded are x=6x = 6 and x=8x = -8.

Final Answer:

  • The product in lowest terms is: 4(x3)3(x6)\frac{-4(x - 3)}{3(x - 6)}.
  • The values of xx to exclude are: x=6x = 6 and x=8x = -8.

Choices:

  • (Choice A) x=8x = -8 — Exclude.
  • (Choice B) x=0x = 0 — Not excluded.
  • (Choice C) x=3x = 3 — Not excluded.
  • (Choice D) x=6x = 6 — Exclude.

Thus, the correct choices are A and D.

Would you like more details or have any questions?
Here are 5 related questions to consider:

  1. How do you factor a quadratic trinomial like x212x+36x^2 - 12x + 36?
  2. What are the steps for simplifying complex fractions like this?
  3. Why do we exclude certain values of xx in rational expressions?
  4. Can you explain how to find the domain of a rational expression in general?
  5. How does factoring help simplify expressions before multiplication?

Tip: Always factor fully before canceling common terms in rational expressions to simplify accurately.

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Math Problem Analysis

Mathematical Concepts

Algebra
Rational Expressions
Factoring
Excluded Values

Formulas

Factoring quadratics: x^2 - 12x + 36 = (x - 6)^2, x^2 - 9x + 18 = (x - 6)(x - 3)
Simplification of rational expressions
Excluded values: set denominator equal to zero and solve

Theorems

Zero Product Property
Properties of Rational Expressions

Suitable Grade Level

Grades 9-12