Math Problem Statement

Simplify the expression \( \frac{3x + 6}{x^2 - 9} \div \frac{6x^2 + 12x}{4x + 12} \).

Solution

The expression you uploaded is:

3x+6x29÷6x2+12x4x+12\frac{3x + 6}{x^2 - 9} \div \frac{6x^2 + 12x}{4x + 12}

Let's simplify it step by step:

Step 1: Factorize all terms.

  • 3x+63x + 6 can be factored as 3(x+2)3(x + 2).
  • x29x^2 - 9 is a difference of squares: (x3)(x+3)(x - 3)(x + 3).
  • 6x2+12x6x^2 + 12x can be factored as 6x(x+2)6x(x + 2).
  • 4x+124x + 12 can be factored as 4(x+3)4(x + 3).

So the expression becomes:

3(x+2)(x3)(x+3)÷6x(x+2)4(x+3)\frac{3(x + 2)}{(x - 3)(x + 3)} \div \frac{6x(x + 2)}{4(x + 3)}

Step 2: Convert division into multiplication.

When dividing by a fraction, we multiply by its reciprocal:

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

Step 3: Simplify the expression.

  • Cancel out (x+2)(x + 2) from both the numerator and denominator.
  • Cancel out (x+3)(x + 3) from both the numerator and denominator.
  • Simplify the constant terms: 3×46x=126x=2x\frac{3 \times 4}{6x} = \frac{12}{6x} = \frac{2}{x}.

So, the simplified expression is:

2x3\frac{2}{x - 3}

This is the final simplified form.

Would you like further details on this or have any questions?


Here are 5 related questions to expand on the solution:

  1. How would you factor more complex quadratic expressions?
  2. What other methods can be used to simplify rational expressions?
  3. What happens if x=3x = 3 in the original expression?
  4. How does the concept of reciprocal division work for algebraic fractions?
  5. How do you handle more complicated division of rational expressions?

Tip: Always check for common factors to cancel in both the numerator and the denominator before performing operations.

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Math Problem Analysis

Mathematical Concepts

Algebra
Factorization
Rational Expressions

Formulas

Factorization of quadratic expressions: x^2 - a^2 = (x - a)(x + a)
Multiplication and division of rational expressions

Theorems

Difference of squares: x^2 - 9 = (x - 3)(x + 3)
Reciprocal property of division in rational expressions

Suitable Grade Level

Grades 9-11