Math Problem Statement

Simplify the expression: \frac{3}{x} - \frac{6}{x + 3} - \frac{x}{(x + 3)^2}.

Solution

The expression in the image is:

3x6x+3x(x+3)2\frac{3}{x} - \frac{6}{x + 3} - \frac{x}{(x + 3)^2}

To simplify this expression, we need to combine the terms by finding a common denominator. Let's go step by step.

Step 1: Identify a common denominator

The denominators are xx, x+3x+3, and (x+3)2(x+3)^2. The least common denominator (LCD) for these is x(x+3)2x(x + 3)^2.

Step 2: Rewrite each term with the LCD as the denominator

We'll rewrite each fraction to have the common denominator x(x+3)2x(x + 3)^2.

  • For 3x\frac{3}{x}, multiply both the numerator and denominator by (x+3)2(x + 3)^2: 3x=3(x+3)2x(x+3)2\frac{3}{x} = \frac{3(x + 3)^2}{x(x + 3)^2}

  • For 6x+3\frac{6}{x+3}, multiply both the numerator and denominator by x(x+3)x(x + 3): 6x+3=6x(x+3)x(x+3)2\frac{6}{x + 3} = \frac{6x(x + 3)}{x(x + 3)^2}

  • For x(x+3)2\frac{x}{(x+3)^2}, the denominator is already (x+3)2(x+3)^2, so just multiply by xx to get the LCD: x(x+3)2=x2x(x+3)2\frac{x}{(x+3)^2} = \frac{x^2}{x(x + 3)^2}

Step 3: Combine the terms

Now, we combine all three terms over the common denominator x(x+3)2x(x + 3)^2:

3(x+3)2x(x+3)26x(x+3)x(x+3)2x2x(x+3)2\frac{3(x + 3)^2}{x(x + 3)^2} - \frac{6x(x + 3)}{x(x + 3)^2} - \frac{x^2}{x(x + 3)^2}

Simplify the numerators:

  • Expand 3(x+3)23(x + 3)^2: 3(x+3)2=3(x2+6x+9)=3x2+18x+273(x + 3)^2 = 3(x^2 + 6x + 9) = 3x^2 + 18x + 27

  • Expand 6x(x+3)6x(x + 3): 6x(x+3)=6x2+18x6x(x + 3) = 6x^2 + 18x

So the expression becomes:

3x2+18x+27x(x+3)26x2+18xx(x+3)2x2x(x+3)2\frac{3x^2 + 18x + 27}{x(x + 3)^2} - \frac{6x^2 + 18x}{x(x + 3)^2} - \frac{x^2}{x(x + 3)^2}

Step 4: Combine the numerators

Now, combine the numerators:

(3x2+18x+27)(6x2+18x)x2(3x^2 + 18x + 27) - (6x^2 + 18x) - x^2

Simplify:

3x2+18x+276x218xx2=4x2+273x^2 + 18x + 27 - 6x^2 - 18x - x^2 = -4x^2 + 27

Step 5: Final expression

The final simplified expression is:

4x2+27x(x+3)2\frac{-4x^2 + 27}{x(x + 3)^2}

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

5 Related Questions:

  1. How do you find the least common denominator for more complex fractions?
  2. What is the difference between simplifying a fraction and factoring it?
  3. How do you expand and simplify expressions involving binomials like (x+3)2(x+3)^2?
  4. Can you explain how to handle negative exponents in similar expressions?
  5. How can you check if a rational expression can be simplified further?

Tip:

When simplifying rational expressions, always look for common factors in the numerator and denominator to potentially reduce the expression further.

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Math Problem Analysis

Mathematical Concepts

Algebra
Rational Expressions
Simplification
Factoring

Formulas

Common Denominator: LCD(x, x+3, (x+3)^2) = x(x + 3)^2

Theorems

Least Common Denominator
Binomial Expansion

Suitable Grade Level

Grades 9-12