Math Problem Statement

resuelve

14. Opera la división y simplifica: \( \frac{2x^2 - 8x}{x^2 - 4} \div \frac{x - 2}{x + 2} \) (Pista: factoriza el numerador y el denominador para cancelar factores comunes.) 15. Multiplica y reduce la siguiente expresión: \( \frac{x^2 + 2x}{x^2 - x - 6} \times \frac{x + 3}{x^2 - 9} \) (Pista: identifica factorizaciones en ambos numeradores y denominadores.)

Solution

Let's solve the two problems from the image one by one.

Problem 14: Simplify the division

2x28xx24÷x2x+2\frac{2x^2 - 8x}{x^2 - 4} \div \frac{x - 2}{x + 2}

Step 1: Factorize the numerator and denominator of each expression.

  • The numerator of the first fraction, 2x28x2x^2 - 8x, can be factored as: 2x(x4)2x(x - 4)
  • The denominator of the first fraction, x24x^2 - 4, is a difference of squares, so it can be factored as: (x2)(x+2)(x - 2)(x + 2)

So the expression becomes:

2x(x4)(x2)(x+2)÷x2x+2\frac{2x(x - 4)}{(x - 2)(x + 2)} \div \frac{x - 2}{x + 2}

Step 2: Convert the division to multiplication.

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

2x(x4)(x2)(x+2)×x+2x2\frac{2x(x - 4)}{(x - 2)(x + 2)} \times \frac{x + 2}{x - 2}

Step 3: Cancel out common factors.

We have (x+2)(x + 2) in both the numerator and denominator, and (x2)(x - 2) in both the numerator and denominator, so we can cancel them:

2x(x4)1\frac{2x(x - 4)}{1}

Step 4: Simplify the result.

Now, we are left with:

2x(x4)2x(x - 4)

Thus, the simplified expression is:

2x(x4)2x(x - 4)

Problem 15: Multiply and simplify the expression

x2+2xx2x6×x+3x29\frac{x^2 + 2x}{x^2 - x - 6} \times \frac{x + 3}{x^2 - 9}

Step 1: Factorize the expressions.

  • The numerator x2+2xx^2 + 2x can be factored as: x(x+2)x(x + 2)
  • The denominator x2x6x^2 - x - 6 can be factored as: (x3)(x+2)(x - 3)(x + 2)
  • The denominator x29x^2 - 9 is a difference of squares and factors as: (x3)(x+3)(x - 3)(x + 3)

So, the expression becomes:

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

Step 2: Multiply the fractions.

Multiply the numerators and the denominators:

x(x+2)(x+3)(x3)(x+2)(x3)(x+3)\frac{x(x + 2)(x + 3)}{(x - 3)(x + 2)(x - 3)(x + 3)}

Step 3: Cancel out common factors.

We have (x+2)(x + 2) and (x+3)(x + 3) in both the numerator and denominator, so we can cancel them:

x(x3)2\frac{x}{(x - 3)^2}

Thus, the simplified result is:

x(x3)2\frac{x}{(x - 3)^2}

Final Answers:

  • Problem 14: The simplified expression is 2x(x4)2x(x - 4).
  • Problem 15: The simplified expression is x(x3)2\frac{x}{(x - 3)^2}.

Would you like further explanation on any of the steps or have additional questions? Here are some related questions for further practice:

  1. How would you factorize the expression x29x^2 - 9 using the difference of squares?
  2. Can you explain why we canceled the (x+2)(x + 2) and (x+3)(x + 3) factors in Problem 15?
  3. How would you simplify a fraction with multiple variables in the numerator and denominator?
  4. What happens if you try to divide two expressions that do not have any common factors?
  5. How do you check your work when simplifying algebraic fractions?

Tip: Always look for common factors in the numerator and denominator before multiplying or dividing expressions to simplify the process.

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Math Problem Analysis

Mathematical Concepts

Algebra
Factoring
Simplifying Expressions
Rational Expressions

Formulas

Difference of Squares
Factorization
Multiplication and Division of Rational Expressions

Theorems

Difference of Squares Theorem
Factor Theorem

Suitable Grade Level

Grades 8-10