Calculus Examples

$p (x) = \frac{x - 4}{x^{3} - 16 x}$

Step 1

Differentiate using the Quotient Rule which states that $\frac{d}{d x} [\frac{f (x)}{g (x)}]$ is $\frac{g (x) \frac{d}{d x} [f (x)] - f (x) \frac{d}{d x} [g (x)]}{{g (x)}^{2}}$ where $f (x) = x - 4$ and $g (x) = x^{3} - 16 x$ .

$\frac{(x^{3} - 16 x) \frac{d}{d x} [x - 4] - (x - 4) \frac{d}{d x} [x^{3} - 16 x]}{{(x^{3} - 16 x)}^{2}}$

Step 2

Differentiate.

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Step 2.1

By the Sum Rule, the derivative of $x - 4$ with respect to $x$ is $\frac{d}{d x} [x] + \frac{d}{d x} [- 4]$ .

$\frac{(x^{3} - 16 x) (\frac{d}{d x} [x] + \frac{d}{d x} [- 4]) - (x - 4) \frac{d}{d x} [x^{3} - 16 x]}{{(x^{3} - 16 x)}^{2}}$

Step 2.2

Differentiate using the Power Rule which states that $\frac{d}{d x} [x^{n}]$ is $n x^{n - 1}$ where $n = 1$ .

$\frac{(x^{3} - 16 x) (1 + \frac{d}{d x} [- 4]) - (x - 4) \frac{d}{d x} [x^{3} - 16 x]}{{(x^{3} - 16 x)}^{2}}$

Step 2.3

Since $- 4$ is constant with respect to $x$ , the derivative of $- 4$ with respect to $x$ is $0$ .

$\frac{(x^{3} - 16 x) (1 + 0) - (x - 4) \frac{d}{d x} [x^{3} - 16 x]}{{(x^{3} - 16 x)}^{2}}$

Step 2.4

Simplify the expression.

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Step 2.4.1

Add $1$ and $0$ .

$\frac{(x^{3} - 16 x) \cdot 1 - (x - 4) \frac{d}{d x} [x^{3} - 16 x]}{{(x^{3} - 16 x)}^{2}}$

Step 2.4.2

Multiply $x^{3} - 16 x$ by $1$ .

$\frac{x^{3} - 16 x - (x - 4) \frac{d}{d x} [x^{3} - 16 x]}{{(x^{3} - 16 x)}^{2}}$

Step 2.5

By the Sum Rule, the derivative of $x^{3} - 16 x$ with respect to $x$ is $\frac{d}{d x} [x^{3}] + \frac{d}{d x} [- 16 x]$ .

$\frac{x^{3} - 16 x - (x - 4) (\frac{d}{d x} [x^{3}] + \frac{d}{d x} [- 16 x])}{{(x^{3} - 16 x)}^{2}}$

Step 2.6

Differentiate using the Power Rule which states that $\frac{d}{d x} [x^{n}]$ is $n x^{n - 1}$ where $n = 3$ .

$\frac{x^{3} - 16 x - (x - 4) (3 x^{2} + \frac{d}{d x} [- 16 x])}{{(x^{3} - 16 x)}^{2}}$

Step 2.7

Since $- 16$ is constant with respect to $x$ , the derivative of $- 16 x$ with respect to $x$ is $- 16 \frac{d}{d x} [x]$ .

$\frac{x^{3} - 16 x - (x - 4) (3 x^{2} - 16 \frac{d}{d x} [x])}{{(x^{3} - 16 x)}^{2}}$

Step 2.8

Differentiate using the Power Rule which states that $\frac{d}{d x} [x^{n}]$ is $n x^{n - 1}$ where $n = 1$ .

$\frac{x^{3} - 16 x - (x - 4) (3 x^{2} - 16 \cdot 1)}{{(x^{3} - 16 x)}^{2}}$

Step 2.9

Multiply $- 16$ by $1$ .

$\frac{x^{3} - 16 x - (x - 4) (3 x^{2} - 16)}{{(x^{3} - 16 x)}^{2}}$

Step 3

Simplify.

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Step 3.1

Apply the distributive property.

$\frac{x^{3} - 16 x + (- x - - 4) (3 x^{2} - 16)}{{(x^{3} - 16 x)}^{2}}$

Step 3.2

Simplify the numerator.

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Step 3.2.1

Simplify each term.

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Step 3.2.1.1

Multiply $- 1$ by $- 4$ .

$\frac{x^{3} - 16 x + (- x + 4) (3 x^{2} - 16)}{{(x^{3} - 16 x)}^{2}}$

Step 3.2.1.2

Expand $(- x + 4) (3 x^{2} - 16)$ using the FOIL Method.

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Step 3.2.1.2.1

Apply the distributive property.

$\frac{x^{3} - 16 x - x (3 x^{2} - 16) + 4 (3 x^{2} - 16)}{{(x^{3} - 16 x)}^{2}}$

Step 3.2.1.2.2

Apply the distributive property.

$\frac{x^{3} - 16 x - x (3 x^{2}) - x \cdot - 16 + 4 (3 x^{2} - 16)}{{(x^{3} - 16 x)}^{2}}$

Step 3.2.1.2.3

Apply the distributive property.

$\frac{x^{3} - 16 x - x (3 x^{2}) - x \cdot - 16 + 4 (3 x^{2}) + 4 \cdot - 16}{{(x^{3} - 16 x)}^{2}}$

Step 3.2.1.3

Simplify each term.

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Step 3.2.1.3.1

Rewrite using the commutative property of multiplication.

$\frac{x^{3} - 16 x - 1 \cdot 3 x \cdot x^{2} - x \cdot - 16 + 4 (3 x^{2}) + 4 \cdot - 16}{{(x^{3} - 16 x)}^{2}}$

Step 3.2.1.3.2

Multiply $x$ by $x^{2}$ by adding the exponents.

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Step 3.2.1.3.2.1

Move $x^{2}$ .

$\frac{x^{3} - 16 x - 1 \cdot 3 (x^{2} x) - x \cdot - 16 + 4 (3 x^{2}) + 4 \cdot - 16}{{(x^{3} - 16 x)}^{2}}$

Step 3.2.1.3.2.2

Multiply $x^{2}$ by $x$ .

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Step 3.2.1.3.2.2.1

Raise $x$ to the power of $1$ .

$\frac{x^{3} - 16 x - 1 \cdot 3 (x^{2} x^{1}) - x \cdot - 16 + 4 (3 x^{2}) + 4 \cdot - 16}{{(x^{3} - 16 x)}^{2}}$

Step 3.2.1.3.2.2.2

Use the power rule $a^{m} a^{n} = a^{m + n}$ to combine exponents.

$\frac{x^{3} - 16 x - 1 \cdot 3 x^{2 + 1} - x \cdot - 16 + 4 (3 x^{2}) + 4 \cdot - 16}{{(x^{3} - 16 x)}^{2}}$

Step 3.2.1.3.2.3

Add $2$ and $1$ .

$\frac{x^{3} - 16 x - 1 \cdot 3 x^{3} - x \cdot - 16 + 4 (3 x^{2}) + 4 \cdot - 16}{{(x^{3} - 16 x)}^{2}}$

Step 3.2.1.3.3

Multiply $- 1$ by $3$ .

$\frac{x^{3} - 16 x - 3 x^{3} - x \cdot - 16 + 4 (3 x^{2}) + 4 \cdot - 16}{{(x^{3} - 16 x)}^{2}}$

Step 3.2.1.3.4

Multiply $- 16$ by $- 1$ .

$\frac{x^{3} - 16 x - 3 x^{3} + 16 x + 4 (3 x^{2}) + 4 \cdot - 16}{{(x^{3} - 16 x)}^{2}}$

Step 3.2.1.3.5

Multiply $3$ by $4$ .

$\frac{x^{3} - 16 x - 3 x^{3} + 16 x + 12 x^{2} + 4 \cdot - 16}{{(x^{3} - 16 x)}^{2}}$

Step 3.2.1.3.6

Multiply $4$ by $- 16$ .

$\frac{x^{3} - 16 x - 3 x^{3} + 16 x + 12 x^{2} - 64}{{(x^{3} - 16 x)}^{2}}$

Step 3.2.2

Combine the opposite terms in $x^{3} - 16 x - 3 x^{3} + 16 x + 12 x^{2} - 64$ .

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Step 3.2.2.1

Add $- 16 x$ and $16 x$ .

$\frac{x^{3} - 3 x^{3} + 0 + 12 x^{2} - 64}{{(x^{3} - 16 x)}^{2}}$

Step 3.2.2.2

Add $x^{3} - 3 x^{3}$ and $0$ .

$\frac{x^{3} - 3 x^{3} + 12 x^{2} - 64}{{(x^{3} - 16 x)}^{2}}$

Step 3.2.3

Subtract $3 x^{3}$ from $x^{3}$ .

$\frac{- 2 x^{3} + 12 x^{2} - 64}{{(x^{3} - 16 x)}^{2}}$

Step 3.3

Factor $2$ out of $- 2 x^{3} + 12 x^{2} - 64$ .

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Step 3.3.1

Factor $2$ out of $- 2 x^{3}$ .

$\frac{2 (- x^{3}) + 12 x^{2} - 64}{{(x^{3} - 16 x)}^{2}}$

Step 3.3.2

Factor $2$ out of $12 x^{2}$ .

$\frac{2 (- x^{3}) + 2 (6 x^{2}) - 64}{{(x^{3} - 16 x)}^{2}}$

Step 3.3.3

Factor $2$ out of $- 64$ .

$\frac{2 (- x^{3}) + 2 (6 x^{2}) + 2 (- 32)}{{(x^{3} - 16 x)}^{2}}$

Step 3.3.4

Factor $2$ out of $2 (- x^{3}) + 2 (6 x^{2})$ .

$\frac{2 (- x^{3} + 6 x^{2}) + 2 (- 32)}{{(x^{3} - 16 x)}^{2}}$

Step 3.3.5

Factor $2$ out of $2 (- x^{3} + 6 x^{2}) + 2 (- 32)$ .

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{{(x^{3} - 16 x)}^{2}}$

Step 3.4

Simplify the denominator.

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Step 3.4.1

Factor $x$ out of $x^{3} - 16 x$ .

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Step 3.4.1.1

Factor $x$ out of $x^{3}$ .

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{{(x \cdot x^{2} - 16 x)}^{2}}$

Step 3.4.1.2

Factor $x$ out of $- 16 x$ .

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{{(x \cdot x^{2} + x \cdot - 16)}^{2}}$

Step 3.4.1.3

Factor $x$ out of $x \cdot x^{2} + x \cdot - 16$ .

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{{(x (x^{2} - 16))}^{2}}$

Step 3.4.2

Rewrite $16$ as $4^{2}$ .

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{{(x (x^{2} - 4^{2}))}^{2}}$

Step 3.4.3

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 $b = 4$ .

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{{(x (x + 4) (x - 4))}^{2}}$

Step 3.4.4

Apply the product rule to $x (x + 4) (x - 4)$ .

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{{(x (x + 4))}^{2} {(x - 4)}^{2}}$

Step 3.4.5

Apply the distributive property.

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{{(x \cdot x + x \cdot 4)}^{2} {(x - 4)}^{2}}$

Step 3.4.6

Multiply $x$ by $x$ .

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{{(x^{2} + x \cdot 4)}^{2} {(x - 4)}^{2}}$

Step 3.4.7

Move $4$ to the left of $x$ .

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{{(x^{2} + 4 \cdot x)}^{2} {(x - 4)}^{2}}$

Step 3.4.8

Rewrite ${(x^{2} + 4 x)}^{2}$ as $(x^{2} + 4 x) (x^{2} + 4 x)$ .

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{(x^{2} + 4 x) (x^{2} + 4 x) {(x - 4)}^{2}}$

Step 3.4.9

Expand $(x^{2} + 4 x) (x^{2} + 4 x)$ using the FOIL Method.

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Step 3.4.9.1

Apply the distributive property.

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{(x^{2} (x^{2} + 4 x) + 4 x (x^{2} + 4 x)) {(x - 4)}^{2}}$

Step 3.4.9.2

Apply the distributive property.

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{(x^{2} x^{2} + x^{2} (4 x) + 4 x (x^{2} + 4 x)) {(x - 4)}^{2}}$

Step 3.4.9.3

Apply the distributive property.

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{(x^{2} x^{2} + x^{2} (4 x) + 4 x \cdot x^{2} + 4 x (4 x)) {(x - 4)}^{2}}$

Step 3.4.10

Simplify and combine like terms.

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Step 3.4.10.1

Simplify each term.

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Step 3.4.10.1.1

Multiply $x^{2}$ by $x^{2}$ by adding the exponents.

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Step 3.4.10.1.1.1

Use the power rule $a^{m} a^{n} = a^{m + n}$ to combine exponents.

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{(x^{2 + 2} + x^{2} (4 x) + 4 x \cdot x^{2} + 4 x (4 x)) {(x - 4)}^{2}}$

Step 3.4.10.1.1.2

Add $2$ and $2$ .

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{(x^{4} + x^{2} (4 x) + 4 x \cdot x^{2} + 4 x (4 x)) {(x - 4)}^{2}}$

Step 3.4.10.1.2

Rewrite using the commutative property of multiplication.

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{(x^{4} + 4 x^{2} x + 4 x \cdot x^{2} + 4 x (4 x)) {(x - 4)}^{2}}$

Step 3.4.10.1.3

Multiply $x^{2}$ by $x$ by adding the exponents.

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Step 3.4.10.1.3.1

Move $x$ .

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{(x^{4} + 4 (x \cdot x^{2}) + 4 x \cdot x^{2} + 4 x (4 x)) {(x - 4)}^{2}}$

Step 3.4.10.1.3.2

Multiply $x$ by $x^{2}$ .

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Step 3.4.10.1.3.2.1

Raise $x$ to the power of $1$ .

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{(x^{4} + 4 (x^{1} x^{2}) + 4 x \cdot x^{2} + 4 x (4 x)) {(x - 4)}^{2}}$

Step 3.4.10.1.3.2.2

Use the power rule $a^{m} a^{n} = a^{m + n}$ to combine exponents.

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{(x^{4} + 4 x^{1 + 2} + 4 x \cdot x^{2} + 4 x (4 x)) {(x - 4)}^{2}}$

Step 3.4.10.1.3.3

Add $1$ and $2$ .

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{(x^{4} + 4 x^{3} + 4 x \cdot x^{2} + 4 x (4 x)) {(x - 4)}^{2}}$

Step 3.4.10.1.4

Multiply $x$ by $x^{2}$ by adding the exponents.

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Step 3.4.10.1.4.1

Move $x^{2}$ .

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{(x^{4} + 4 x^{3} + 4 (x^{2} x) + 4 x (4 x)) {(x - 4)}^{2}}$

Step 3.4.10.1.4.2

Multiply $x^{2}$ by $x$ .

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Step 3.4.10.1.4.2.1

Raise $x$ to the power of $1$ .

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{(x^{4} + 4 x^{3} + 4 (x^{2} x^{1}) + 4 x (4 x)) {(x - 4)}^{2}}$

Step 3.4.10.1.4.2.2

Use the power rule $a^{m} a^{n} = a^{m + n}$ to combine exponents.

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{(x^{4} + 4 x^{3} + 4 x^{2 + 1} + 4 x (4 x)) {(x - 4)}^{2}}$

Step 3.4.10.1.4.3

Add $2$ and $1$ .

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{(x^{4} + 4 x^{3} + 4 x^{3} + 4 x (4 x)) {(x - 4)}^{2}}$

Step 3.4.10.1.5

Rewrite using the commutative property of multiplication.

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{(x^{4} + 4 x^{3} + 4 x^{3} + 4 \cdot 4 x \cdot x) {(x - 4)}^{2}}$

Step 3.4.10.1.6

Multiply $x$ by $x$ by adding the exponents.

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Step 3.4.10.1.6.1

Move $x$ .

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{(x^{4} + 4 x^{3} + 4 x^{3} + 4 \cdot 4 (x \cdot x)) {(x - 4)}^{2}}$

Step 3.4.10.1.6.2

Multiply $x$ by $x$ .

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{(x^{4} + 4 x^{3} + 4 x^{3} + 4 \cdot 4 x^{2}) {(x - 4)}^{2}}$

Step 3.4.10.1.7

Multiply $4$ by $4$ .

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{(x^{4} + 4 x^{3} + 4 x^{3} + 16 x^{2}) {(x - 4)}^{2}}$

Step 3.4.10.2

Add $4 x^{3}$ and $4 x^{3}$ .

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{(x^{4} + 8 x^{3} + 16 x^{2}) {(x - 4)}^{2}}$

Step 3.4.11

Factor $x^{2}$ out of $x^{4} + 8 x^{3} + 16 x^{2}$ .

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Step 3.4.11.1

Factor $x^{2}$ out of $x^{4}$ .

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{(x^{2} x^{2} + 8 x^{3} + 16 x^{2}) {(x - 4)}^{2}}$

Step 3.4.11.2

Factor $x^{2}$ out of $8 x^{3}$ .

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{(x^{2} x^{2} + x^{2} (8 x) + 16 x^{2}) {(x - 4)}^{2}}$

Step 3.4.11.3

Factor $x^{2}$ out of $16 x^{2}$ .

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{(x^{2} x^{2} + x^{2} (8 x) + x^{2} \cdot 16) {(x - 4)}^{2}}$

Step 3.4.11.4

Factor $x^{2}$ out of $x^{2} x^{2} + x^{2} (8 x)$ .

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{(x^{2} (x^{2} + 8 x) + x^{2} \cdot 16) {(x - 4)}^{2}}$

Step 3.4.11.5

Factor $x^{2}$ out of $x^{2} (x^{2} + 8 x) + x^{2} \cdot 16$ .

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{x^{2} (x^{2} + 8 x + 16) {(x - 4)}^{2}}$

Step 3.4.12

Factor using the perfect square rule.

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Step 3.4.12.1

Rewrite $16$ as $4^{2}$ .

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{x^{2} (x^{2} + 8 x + 4^{2}) {(x - 4)}^{2}}$

Step 3.4.12.2

Check that the middle term is two times the product of the numbers being squared in the first term and third term.

$8 x = 2 \cdot x \cdot 4$

Step 3.4.12.3

Rewrite the polynomial.

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{x^{2} (x^{2} + 2 \cdot x \cdot 4 + 4^{2}) {(x - 4)}^{2}}$

Step 3.4.12.4

Factor using the perfect square trinomial rule $a^{2} + 2 a b + b^{2} = {(a + b)}^{2}$ , where $a = x$ and $b = 4$ .

$\frac{2 (- x^{3} + 6 x^{2} - 32)}{x^{2} {(x + 4)}^{2} {(x - 4)}^{2}}$

Step 3.5

Factor $- 1$ out of $- x^{3}$ .

$\frac{2 (- (x^{3}) + 6 x^{2} - 32)}{x^{2} {(x + 4)}^{2} {(x - 4)}^{2}}$

Step 3.6

Factor $- 1$ out of $6 x^{2}$ .

$\frac{2 (- (x^{3}) - (- 6 x^{2}) - 32)}{x^{2} {(x + 4)}^{2} {(x - 4)}^{2}}$

Step 3.7

Factor $- 1$ out of $- (x^{3}) - (- 6 x^{2})$ .

$\frac{2 (- (x^{3} - 6 x^{2}) - 32)}{x^{2} {(x + 4)}^{2} {(x - 4)}^{2}}$

Step 3.8

Rewrite $- 32$ as $- 1 (32)$ .

$\frac{2 (- (x^{3} - 6 x^{2}) - 1 (32))}{x^{2} {(x + 4)}^{2} {(x - 4)}^{2}}$

Step 3.9

Factor $- 1$ out of $- (x^{3} - 6 x^{2}) - 1 (32)$ .

$\frac{2 (- (x^{3} - 6 x^{2} + 32))}{x^{2} {(x + 4)}^{2} {(x - 4)}^{2}}$

Step 3.10

Rewrite $- (x^{3} - 6 x^{2} + 32)$ as $- 1 (x^{3} - 6 x^{2} + 32)$ .

$\frac{2 (- 1 (x^{3} - 6 x^{2} + 32))}{x^{2} {(x + 4)}^{2} {(x - 4)}^{2}}$

Step 3.11

Move the negative in front of the fraction.

$- \frac{2 (x^{3} - 6 x^{2} + 32)}{x^{2} {(x + 4)}^{2} {(x - 4)}^{2}}$