Algebra Examples

$\frac{6 x^{2} - 216}{x^{2} - 2 x - 48} \cdot \frac{64 - x^{2}}{x^{2} + 13 x + 40} \cdot \frac{- x - 5}{x^{2} - 36}$

Step 1

Simplify the denominator.

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Step 1.1

Rewrite $36$ as $6^{2}$ .

$\frac{6 x^{2} - 216}{x^{2} - 2 x - 48} \cdot \frac{64 - x^{2}}{x^{2} + 13 x + 40} \cdot \frac{- x - 5}{x^{2} - 6^{2}}$

Step 1.2

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 $b = 6$ .

$\frac{6 x^{2} - 216}{x^{2} - 2 x - 48} \cdot \frac{64 - x^{2}}{x^{2} + 13 x + 40} \cdot \frac{- x - 5}{(x + 6) (x - 6)}$

Step 2

Simplify the numerator.

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Step 2.1

Factor $6$ out of $6 x^{2} - 216$ .

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Step 2.1.1

Factor $6$ out of $6 x^{2}$ .

$\frac{6 (x^{2}) - 216}{x^{2} - 2 x - 48} \cdot \frac{64 - x^{2}}{x^{2} + 13 x + 40} \cdot \frac{- x - 5}{(x + 6) (x - 6)}$

Step 2.1.2

Factor $6$ out of $- 216$ .

$\frac{6 x^{2} + 6 \cdot - 36}{x^{2} - 2 x - 48} \cdot \frac{64 - x^{2}}{x^{2} + 13 x + 40} \cdot \frac{- x - 5}{(x + 6) (x - 6)}$

Step 2.1.3

Factor $6$ out of $6 x^{2} + 6 \cdot - 36$ .

$\frac{6 (x^{2} - 36)}{x^{2} - 2 x - 48} \cdot \frac{64 - x^{2}}{x^{2} + 13 x + 40} \cdot \frac{- x - 5}{(x + 6) (x - 6)}$

Step 2.2

Rewrite $36$ as $6^{2}$ .

$\frac{6 (x^{2} - 6^{2})}{x^{2} - 2 x - 48} \cdot \frac{64 - x^{2}}{x^{2} + 13 x + 40} \cdot \frac{- x - 5}{(x + 6) (x - 6)}$

Step 2.3

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 $b = 6$ .

$\frac{6 (x + 6) (x - 6)}{x^{2} - 2 x - 48} \cdot \frac{64 - x^{2}}{x^{2} + 13 x + 40} \cdot \frac{- x - 5}{(x + 6) (x - 6)}$

Step 3

Factor $x^{2} - 2 x - 48$ using the AC method.

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Step 3.1

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 $- 48$ and whose sum is $- 2$ .

$- 8, 6$

Step 3.2

Write the factored form using these integers.

$\frac{6 (x + 6) (x - 6)}{(x - 8) (x + 6)} \cdot \frac{64 - x^{2}}{x^{2} + 13 x + 40} \cdot \frac{- x - 5}{(x + 6) (x - 6)}$

Step 4

Simplify the numerator.

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Step 4.1

Rewrite $64$ as $8^{2}$ .

$\frac{6 (x + 6) (x - 6)}{(x - 8) (x + 6)} \cdot \frac{8^{2} - x^{2}}{x^{2} + 13 x + 40} \cdot \frac{- x - 5}{(x + 6) (x - 6)}$

Step 4.2

Since both terms are perfect squares, factor using the difference of squares formula, $a^{2} - b^{2} = (a + b) (a - b)$ where $a = 8$ and $b = x$ .

$\frac{6 (x + 6) (x - 6)}{(x - 8) (x + 6)} \cdot \frac{(8 + x) (8 - x)}{x^{2} + 13 x + 40} \cdot \frac{- x - 5}{(x + 6) (x - 6)}$

Step 5

Factor $x^{2} + 13 x + 40$ using the AC method.

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Step 5.1

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 $40$ and whose sum is $13$ .

$5, 8$

Step 5.2

Write the factored form using these integers.

$\frac{6 (x + 6) (x - 6)}{(x - 8) (x + 6)} \cdot \frac{(8 + x) (8 - x)}{(x + 5) (x + 8)} \cdot \frac{- x - 5}{(x + 6) (x - 6)}$

Step 6

Simplify terms.

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Step 6.1

Cancel the common factor of $x + 6$ .

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Step 6.1.1

Cancel the common factor.

$\frac{6 (x + 6) (x - 6)}{(x - 8) (x + 6)} \cdot \frac{(8 + x) (8 - x)}{(x + 5) (x + 8)} \cdot \frac{- x - 5}{(x + 6) (x - 6)}$

Step 6.1.2

Rewrite the expression.

$\frac{6 (x - 6)}{x - 8} \cdot \frac{(8 + x) (8 - x)}{(x + 5) (x + 8)} \cdot \frac{- x - 5}{(x + 6) (x - 6)}$

Step 6.2

Cancel the common factor of $8 + x$ and $x + 8$ .

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Step 6.2.1

Reorder terms.

$\frac{6 (x - 6)}{x - 8} \cdot \frac{(x + 8) (8 - x)}{(x + 5) (x + 8)} \cdot \frac{- x - 5}{(x + 6) (x - 6)}$

Step 6.2.2

Cancel the common factor.

$\frac{6 (x - 6)}{x - 8} \cdot \frac{(x + 8) (8 - x)}{(x + 5) (x + 8)} \cdot \frac{- x - 5}{(x + 6) (x - 6)}$

Step 6.2.3

Rewrite the expression.

$\frac{6 (x - 6)}{x - 8} \cdot \frac{8 - x}{x + 5} \cdot \frac{- x - 5}{(x + 6) (x - 6)}$

Step 6.3

Multiply $\frac{6 (x - 6)}{x - 8}$ by $\frac{8 - x}{x + 5}$ .

$\frac{6 (x - 6) (8 - x)}{(x - 8) (x + 5)} \cdot \frac{- x - 5}{(x + 6) (x - 6)}$

Step 6.4

Cancel the common factor of $x - 6$ .

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Step 6.4.1

Factor $x - 6$ out of $6 (x - 6) (8 - x)$ .

$\frac{(x - 6) (6 (8 - x))}{(x - 8) (x + 5)} \cdot \frac{- x - 5}{(x + 6) (x - 6)}$

Step 6.4.2

Factor $x - 6$ out of $(x + 6) (x - 6)$ .

$\frac{(x - 6) (6 (8 - x))}{(x - 8) (x + 5)} \cdot \frac{- x - 5}{(x - 6) (x + 6)}$

Step 6.4.3

Cancel the common factor.

$\frac{(x - 6) (6 (8 - x))}{(x - 8) (x + 5)} \cdot \frac{- x - 5}{(x - 6) (x + 6)}$

Step 6.4.4

Rewrite the expression.

$\frac{6 (8 - x)}{(x - 8) (x + 5)} \cdot \frac{- x - 5}{x + 6}$

Step 6.5

Multiply $\frac{6 (8 - x)}{(x - 8) (x + 5)}$ by $\frac{- x - 5}{x + 6}$ .

$\frac{6 (8 - x) (- x - 5)}{(x - 8) (x + 5) (x + 6)}$

Step 6.6

Cancel the common factor of $8 - x$ and $x - 8$ .

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Step 6.6.1

Rewrite $8$ as $- 1 (- 8)$ .

$\frac{6 (- 1 (- 8) - x) (- x - 5)}{(x - 8) (x + 5) (x + 6)}$

Step 6.6.2

Factor $- 1$ out of $- x$ .

$\frac{6 (- 1 (- 8) - (x)) (- x - 5)}{(x - 8) (x + 5) (x + 6)}$

Step 6.6.3

Factor $- 1$ out of $- 1 (- 8) - (x)$ .

$\frac{6 (- 1 (- 8 + x)) (- x - 5)}{(x - 8) (x + 5) (x + 6)}$

Step 6.6.4

Reorder terms.

$\frac{6 (- 1 (x - 8)) (- x - 5)}{(x - 8) (x + 5) (x + 6)}$

Step 6.6.5

Cancel the common factor.

$\frac{6 (- 1 (x - 8)) (- x - 5)}{(x - 8) (x + 5) (x + 6)}$

Step 6.6.6

Rewrite the expression.

$\frac{6 \cdot (- 1) (- x - 5)}{(x + 5) (x + 6)}$

Step 6.7

Cancel the common factor of $- x - 5$ and $x + 5$ .

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Step 6.7.1

Factor $- 1$ out of $- x$ .

$\frac{6 \cdot (- 1) (- (x) - 5)}{(x + 5) (x + 6)}$

Step 6.7.2

Rewrite $- 5$ as $- 1 (5)$ .

$\frac{6 \cdot (- 1) (- (x) - 1 (5))}{(x + 5) (x + 6)}$

Step 6.7.3

Factor $- 1$ out of $- (x) - 1 (5)$ .

$\frac{6 \cdot (- 1) (- (x + 5))}{(x + 5) (x + 6)}$

Step 6.7.4

Rewrite $- (x + 5)$ as $- 1 (x + 5)$ .

$\frac{6 \cdot (- 1) (- 1 (x + 5))}{(x + 5) (x + 6)}$

Step 6.7.5

Cancel the common factor.

$\frac{6 \cdot (- 1) (- 1 (x + 5))}{(x + 5) (x + 6)}$

Step 6.7.6

Rewrite the expression.

$\frac{6 \cdot (- 1) \cdot (- 1)}{x + 6}$

Step 7

Simplify the numerator.

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Step 7.1

Multiply $6$ by $- 1$ .

$\frac{- 6 \cdot - 1}{x + 6}$

Step 7.2

Multiply $- 6$ by $- 1$ .

$\frac{6}{x + 6}$