Algebra Examples

$\frac{\frac{4}{x^{2} - 9} + \frac{2}{x - 3}}{\frac{1}{x + 3} + \frac{1}{x - 3}}$

Step 1

Multiply the numerator and denominator of the fraction by $(x^{2} - 9) (x - 3) (x + 3)$ .

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Step 1.1

Multiply $\frac{\frac{4}{x^{2} - 9} + \frac{2}{x - 3}}{\frac{1}{x + 3} + \frac{1}{x - 3}}$ by $\frac{(x^{2} - 9) (x - 3) (x + 3)}{(x^{2} - 9) (x - 3) (x + 3)}$ .

$\frac{(x^{2} - 9) (x - 3) (x + 3)}{(x^{2} - 9) (x - 3) (x + 3)} \cdot \frac{\frac{4}{x^{2} - 9} + \frac{2}{x - 3}}{\frac{1}{x + 3} + \frac{1}{x - 3}}$

Step 1.2

Combine.

$\frac{(x^{2} - 9) (x - 3) (x + 3) (\frac{4}{x^{2} - 9} + \frac{2}{x - 3})}{(x^{2} - 9) (x - 3) (x + 3) (\frac{1}{x + 3} + \frac{1}{x - 3})}$

Step 2

Apply the distributive property.

$\frac{(x^{2} - 9) (x - 3) (x + 3) \frac{4}{x^{2} - 9} + (x^{2} - 9) (x - 3) (x + 3) \frac{2}{x - 3}}{(x^{2} - 9) (x - 3) (x + 3) \frac{1}{x + 3} + (x^{2} - 9) (x - 3) (x + 3) \frac{1}{x - 3}}$

Step 3

Simplify by cancelling.

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Step 3.1

Cancel the common factor of $x^{2} - 9$ .

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Step 3.1.1

Factor $x^{2} - 9$ out of $(x^{2} - 9) (x - 3) (x + 3)$ .

$\frac{(x^{2} - 9) ((x - 3) (x + 3)) \frac{4}{x^{2} - 9} + (x^{2} - 9) (x - 3) (x + 3) \frac{2}{x - 3}}{(x^{2} - 9) (x - 3) (x + 3) \frac{1}{x + 3} + (x^{2} - 9) (x - 3) (x + 3) \frac{1}{x - 3}}$

Step 3.1.2

Cancel the common factor.

$\frac{(x^{2} - 9) ((x - 3) (x + 3)) \frac{4}{x^{2} - 9} + (x^{2} - 9) (x - 3) (x + 3) \frac{2}{x - 3}}{(x^{2} - 9) (x - 3) (x + 3) \frac{1}{x + 3} + (x^{2} - 9) (x - 3) (x + 3) \frac{1}{x - 3}}$

Step 3.1.3

Rewrite the expression.

$\frac{(x - 3) (x + 3) \cdot 4 + (x^{2} - 9) (x - 3) (x + 3) \frac{2}{x - 3}}{(x^{2} - 9) (x - 3) (x + 3) \frac{1}{x + 3} + (x^{2} - 9) (x - 3) (x + 3) \frac{1}{x - 3}}$

Step 3.2

Cancel the common factor of $x - 3$ .

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Step 3.2.1

Factor $x - 3$ out of $(x^{2} - 9) (x - 3) (x + 3)$ .

$\frac{(x - 3) (x + 3) \cdot 4 + (x - 3) ((x^{2} - 9) (x + 3)) \frac{2}{x - 3}}{(x^{2} - 9) (x - 3) (x + 3) \frac{1}{x + 3} + (x^{2} - 9) (x - 3) (x + 3) \frac{1}{x - 3}}$

Step 3.2.2

Cancel the common factor.

$\frac{(x - 3) (x + 3) \cdot 4 + (x - 3) ((x^{2} - 9) (x + 3)) \frac{2}{x - 3}}{(x^{2} - 9) (x - 3) (x + 3) \frac{1}{x + 3} + (x^{2} - 9) (x - 3) (x + 3) \frac{1}{x - 3}}$

Step 3.2.3

Rewrite the expression.

$\frac{(x - 3) (x + 3) \cdot 4 + (x^{2} - 9) (x + 3) \cdot 2}{(x^{2} - 9) (x - 3) (x + 3) \frac{1}{x + 3} + (x^{2} - 9) (x - 3) (x + 3) \frac{1}{x - 3}}$

Step 3.3

Cancel the common factor of $x + 3$ .

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Step 3.3.1

Factor $x + 3$ out of $(x^{2} - 9) (x - 3) (x + 3)$ .

$\frac{(x - 3) (x + 3) \cdot 4 + (x^{2} - 9) (x + 3) \cdot 2}{(x + 3) ((x^{2} - 9) (x - 3)) \frac{1}{x + 3} + (x^{2} - 9) (x - 3) (x + 3) \frac{1}{x - 3}}$

Step 3.3.2

Cancel the common factor.

$\frac{(x - 3) (x + 3) \cdot 4 + (x^{2} - 9) (x + 3) \cdot 2}{(x + 3) ((x^{2} - 9) (x - 3)) \frac{1}{x + 3} + (x^{2} - 9) (x - 3) (x + 3) \frac{1}{x - 3}}$

Step 3.3.3

Rewrite the expression.

$\frac{(x - 3) (x + 3) \cdot 4 + (x^{2} - 9) (x + 3) \cdot 2}{(x^{2} - 9) (x - 3) + (x^{2} - 9) (x - 3) (x + 3) \frac{1}{x - 3}}$

Step 3.4

Cancel the common factor of $x - 3$ .

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Step 3.4.1

Factor $x - 3$ out of $(x^{2} - 9) (x - 3) (x + 3)$ .

$\frac{(x - 3) (x + 3) \cdot 4 + (x^{2} - 9) (x + 3) \cdot 2}{(x^{2} - 9) (x - 3) + (x - 3) ((x^{2} - 9) (x + 3)) \frac{1}{x - 3}}$

Step 3.4.2

Cancel the common factor.

$\frac{(x - 3) (x + 3) \cdot 4 + (x^{2} - 9) (x + 3) \cdot 2}{(x^{2} - 9) (x - 3) + (x - 3) ((x^{2} - 9) (x + 3)) \frac{1}{x - 3}}$

Step 3.4.3

Rewrite the expression.

$\frac{(x - 3) (x + 3) \cdot 4 + (x^{2} - 9) (x + 3) \cdot 2}{(x^{2} - 9) (x - 3) + (x^{2} - 9) (x + 3)}$

Step 4

Simplify the numerator.

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Step 4.1

Factor $(x + 3) \cdot 2$ out of $(x - 3) (x + 3) \cdot 4 + (x^{2} - 9) (x + 3) \cdot 2$ .

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Step 4.1.1

Factor $(x + 3) \cdot 2$ out of $(x - 3) (x + 3) \cdot 4$ .

$\frac{(x + 3) \cdot 2 ((x - 3) \cdot 2) + (x^{2} - 9) (x + 3) \cdot 2}{(x^{2} - 9) (x - 3) + (x^{2} - 9) (x + 3)}$

Step 4.1.2

Factor $(x + 3) \cdot 2$ out of $(x^{2} - 9) (x + 3) \cdot 2$ .

$\frac{(x + 3) \cdot 2 ((x - 3) \cdot 2) + (x + 3) \cdot 2 (x^{2} - 9)}{(x^{2} - 9) (x - 3) + (x^{2} - 9) (x + 3)}$

Step 4.1.3

Factor $(x + 3) \cdot 2$ out of $(x + 3) \cdot 2 ((x - 3) \cdot 2) + (x + 3) \cdot 2 (x^{2} - 9)$ .

$\frac{(x + 3) \cdot 2 ((x - 3) \cdot 2 + x^{2} - 9)}{(x^{2} - 9) (x - 3) + (x^{2} - 9) (x + 3)}$

Step 4.2

Apply the distributive property.

$\frac{(x + 3) \cdot 2 (x \cdot 2 - 3 \cdot 2 + x^{2} - 9)}{(x^{2} - 9) (x - 3) + (x^{2} - 9) (x + 3)}$

Step 4.3

Move $2$ to the left of $x$ .

$\frac{(x + 3) \cdot 2 (2 \cdot x - 3 \cdot 2 + x^{2} - 9)}{(x^{2} - 9) (x - 3) + (x^{2} - 9) (x + 3)}$

Step 4.4

Multiply $- 3$ by $2$ .

$\frac{(x + 3) \cdot 2 (2 \cdot x - 6 + x^{2} - 9)}{(x^{2} - 9) (x - 3) + (x^{2} - 9) (x + 3)}$

Step 4.5

Subtract $9$ from $- 6$ .

$\frac{(x + 3) \cdot 2 (2 x + x^{2} - 15)}{(x^{2} - 9) (x - 3) + (x^{2} - 9) (x + 3)}$

Step 4.6

Reorder terms.

$\frac{(x + 3) \cdot 2 (x^{2} + 2 x - 15)}{(x^{2} - 9) (x - 3) + (x^{2} - 9) (x + 3)}$

Step 4.7

Factor $x^{2} + 2 x - 15$ using the AC method.

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Step 4.7.1

Consider the form $x^{2} + b x + c$ . Find a pair of integers whose product is $c$ and whose sum is $b$ . In this case, whose product is $- 15$ and whose sum is $2$ .

$- 3, 5$

Step 4.7.2

Write the factored form using these integers.

$\frac{(x + 3) \cdot 2 ((x - 3) (x + 5))}{(x^{2} - 9) (x - 3) + (x^{2} - 9) (x + 3)}$

$\frac{(x + 3) \cdot 2 (x - 3) (x + 5)}{(x^{2} - 9) (x - 3) + (x^{2} - 9) (x + 3)}$

Step 5

Simplify the denominator.

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Step 5.1

Factor $x^{2} - 9$ out of $(x^{2} - 9) (x - 3) + (x^{2} - 9) (x + 3)$ .

$\frac{(x + 3) \cdot 2 (x - 3) (x + 5)}{(x^{2} - 9) (x - 3 + x + 3)}$

Step 5.2

Rewrite $9$ as $3^{2}$ .

$\frac{(x + 3) \cdot 2 (x - 3) (x + 5)}{(x^{2} - 3^{2}) (x - 3 + x + 3)}$

Step 5.3

Since both terms are perfect squares, factor using the difference of squares formula, $a^{2} - b^{2} = (a + b) (a - b)$ where $a = x$ and $b = 3$ .

$\frac{(x + 3) \cdot 2 (x - 3) (x + 5)}{(x + 3) (x - 3) (x - 3 + x + 3)}$

Step 5.4

Add $x$ and $x$ .

$\frac{(x + 3) \cdot 2 (x - 3) (x + 5)}{(x + 3) (x - 3) (2 x - 3 + 3)}$

Step 5.5

Add $- 3$ and $3$ .

$\frac{(x + 3) \cdot 2 (x - 3) (x + 5)}{(x + 3) (x - 3) (2 x + 0)}$

Step 5.6

Add $2 x$ and $0$ .

$\frac{(x + 3) \cdot 2 (x - 3) (x + 5)}{(x + 3) (x - 3) \cdot 2 x}$

Step 6

Reduce the expression by cancelling the common factors.

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Step 6.1

Cancel the common factor of $x + 3$ .

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Step 6.1.1

Cancel the common factor.

$\frac{(x + 3) \cdot 2 (x - 3) (x + 5)}{(x + 3) (x - 3) \cdot 2 x}$

Step 6.1.2

Rewrite the expression.

$\frac{(2 (x - 3)) (x + 5)}{(x - 3) \cdot 2 x}$

Step 6.2

Cancel the common factor of $2$ .

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Step 6.2.1

Cancel the common factor.

$\frac{2 (x - 3) (x + 5)}{(x - 3) \cdot 2 x}$

Step 6.2.2

Rewrite the expression.

$\frac{(x - 3) (x + 5)}{(x - 3) x}$

Step 6.3

Cancel the common factor of $x - 3$ .

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Step 6.3.1

Cancel the common factor.

$\frac{(x - 3) (x + 5)}{(x - 3) x}$

Step 6.3.2

Rewrite the expression.

$\frac{x + 5}{x}$