Algebra Examples

${(x - \frac{1}{x})}^{3}$

Step 1

Use the binomial expansion theorem to find each term. The binomial theorem states ${(a + b)}^{n} = \sum_{k = 0}^{n} n C k \cdot (a^{n - k} b^{k})$ .

$\sum_{k = 0}^{3} \frac{3!}{(3 - k)! k!} \cdot {(x)}^{3 - k} \cdot {(- \frac{1}{x})}^{k}$

Step 2

Expand the summation.

$\frac{3!}{(3 - 0)! 0!} {(x)}^{3 - 0} \cdot {(- \frac{1}{x})}^{0} + \frac{3!}{(3 - 1)! 1!} {(x)}^{3 - 1} \cdot {(- \frac{1}{x})}^{1} + \frac{3!}{(3 - 2)! 2!} {(x)}^{3 - 2} \cdot {(- \frac{1}{x})}^{2} + \frac{3!}{(3 - 3)! 3!} {(x)}^{3 - 3} \cdot {(- \frac{1}{x})}^{3}$

Step 3

Simplify the exponents for each term of the expansion.

$1 \cdot {(x)}^{3} \cdot {(- \frac{1}{x})}^{0} + 3 \cdot {(x)}^{2} \cdot {(- \frac{1}{x})}^{1} + 3 \cdot {(x)}^{1} \cdot {(- \frac{1}{x})}^{2} + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4

Simplify each term.

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Step 4.1

Multiply ${(x)}^{3}$ by $1$ .

${(x)}^{3} \cdot {(- \frac{1}{x})}^{0} + 3 \cdot {(x)}^{2} \cdot {(- \frac{1}{x})}^{1} + 3 \cdot {(x)}^{1} \cdot {(- \frac{1}{x})}^{2} + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.2

Use the power rule ${(a b)}^{n} = a^{n} b^{n}$ to distribute the exponent.

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Step 4.2.1

Apply the product rule to $- \frac{1}{x}$ .

$x^{3} \cdot ({(- 1)}^{0} {(\frac{1}{x})}^{0}) + 3 \cdot {(x)}^{2} \cdot {(- \frac{1}{x})}^{1} + 3 \cdot {(x)}^{1} \cdot {(- \frac{1}{x})}^{2} + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.2.2

Apply the product rule to $\frac{1}{x}$ .

$x^{3} \cdot ({(- 1)}^{0} \frac{1^{0}}{x^{0}}) + 3 \cdot {(x)}^{2} \cdot {(- \frac{1}{x})}^{1} + 3 \cdot {(x)}^{1} \cdot {(- \frac{1}{x})}^{2} + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.3

Rewrite using the commutative property of multiplication.

${(- 1)}^{0} x^{3} \frac{1^{0}}{x^{0}} + 3 \cdot {(x)}^{2} \cdot {(- \frac{1}{x})}^{1} + 3 \cdot {(x)}^{1} \cdot {(- \frac{1}{x})}^{2} + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.4

Cancel the common factor of $x^{0}$ .

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Step 4.4.1

Factor $x^{0}$ out of ${(- 1)}^{0} x^{3}$ .

$x^{0} ({(- 1)}^{0} x^{3}) \frac{1^{0}}{x^{0}} + 3 \cdot {(x)}^{2} \cdot {(- \frac{1}{x})}^{1} + 3 \cdot {(x)}^{1} \cdot {(- \frac{1}{x})}^{2} + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.4.2

Cancel the common factor.

$x^{0} ({(- 1)}^{0} x^{3}) \frac{1^{0}}{x^{0}} + 3 \cdot {(x)}^{2} \cdot {(- \frac{1}{x})}^{1} + 3 \cdot {(x)}^{1} \cdot {(- \frac{1}{x})}^{2} + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.4.3

Rewrite the expression.

${(- 1)}^{0} x^{3} \cdot 1^{0} + 3 \cdot {(x)}^{2} \cdot {(- \frac{1}{x})}^{1} + 3 \cdot {(x)}^{1} \cdot {(- \frac{1}{x})}^{2} + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.5

Anything raised to $0$ is $1$ .

$1 x^{3} \cdot 1^{0} + 3 \cdot {(x)}^{2} \cdot {(- \frac{1}{x})}^{1} + 3 \cdot {(x)}^{1} \cdot {(- \frac{1}{x})}^{2} + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.6

Multiply $1$ by $1^{0}$ by adding the exponents.

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Step 4.6.1

Move $1^{0}$ .

$1^{0} \cdot 1 x^{3} + 3 \cdot {(x)}^{2} \cdot {(- \frac{1}{x})}^{1} + 3 \cdot {(x)}^{1} \cdot {(- \frac{1}{x})}^{2} + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.6.2

Multiply $1^{0}$ by $1$ .

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Step 4.6.2.1

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

$1^{0} \cdot 1^{1} x^{3} + 3 \cdot {(x)}^{2} \cdot {(- \frac{1}{x})}^{1} + 3 \cdot {(x)}^{1} \cdot {(- \frac{1}{x})}^{2} + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.6.2.2

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

$1^{0 + 1} x^{3} + 3 \cdot {(x)}^{2} \cdot {(- \frac{1}{x})}^{1} + 3 \cdot {(x)}^{1} \cdot {(- \frac{1}{x})}^{2} + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.6.3

Add $0$ and $1$ .

$1^{1} x^{3} + 3 \cdot {(x)}^{2} \cdot {(- \frac{1}{x})}^{1} + 3 \cdot {(x)}^{1} \cdot {(- \frac{1}{x})}^{2} + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.7

Simplify $1^{1} x^{3}$ .

$x^{3} + 3 \cdot {(x)}^{2} \cdot {(- \frac{1}{x})}^{1} + 3 \cdot {(x)}^{1} \cdot {(- \frac{1}{x})}^{2} + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.8

Simplify.

$x^{3} + 3 x^{2} \cdot (- \frac{1}{x}) + 3 \cdot {(x)}^{1} \cdot {(- \frac{1}{x})}^{2} + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.9

Cancel the common factor of $x$ .

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Step 4.9.1

Move the leading negative in $- \frac{1}{x}$ into the numerator.

$x^{3} + 3 x^{2} \cdot \frac{- 1}{x} + 3 \cdot {(x)}^{1} \cdot {(- \frac{1}{x})}^{2} + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.9.2

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

$x^{3} + x (3 x) \cdot \frac{- 1}{x} + 3 \cdot {(x)}^{1} \cdot {(- \frac{1}{x})}^{2} + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.9.3

Cancel the common factor.

$x^{3} + x (3 x) \cdot \frac{- 1}{x} + 3 \cdot {(x)}^{1} \cdot {(- \frac{1}{x})}^{2} + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.9.4

Rewrite the expression.

$x^{3} + 3 x \cdot - 1 + 3 \cdot {(x)}^{1} \cdot {(- \frac{1}{x})}^{2} + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.10

Multiply $- 1$ by $3$ .

$x^{3} - 3 x + 3 \cdot {(x)}^{1} \cdot {(- \frac{1}{x})}^{2} + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.11

Simplify.

$x^{3} - 3 x + 3 \cdot x \cdot {(- \frac{1}{x})}^{2} + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.12

Use the power rule ${(a b)}^{n} = a^{n} b^{n}$ to distribute the exponent.

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Step 4.12.1

Apply the product rule to $- \frac{1}{x}$ .

$x^{3} - 3 x + 3 x \cdot ({(- 1)}^{2} {(\frac{1}{x})}^{2}) + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.12.2

Apply the product rule to $\frac{1}{x}$ .

$x^{3} - 3 x + 3 x \cdot ({(- 1)}^{2} \frac{1^{2}}{x^{2}}) + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.13

Raise $- 1$ to the power of $2$ .

$x^{3} - 3 x + 3 x \cdot (1 \frac{1^{2}}{x^{2}}) + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.14

Multiply $\frac{1^{2}}{x^{2}}$ by $1$ .

$x^{3} - 3 x + 3 x \cdot \frac{1^{2}}{x^{2}} + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.15

One to any power is one.

$x^{3} - 3 x + 3 x \cdot \frac{1}{x^{2}} + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.16

Cancel the common factor of $x$ .

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Step 4.16.1

Factor $x$ out of $3 x$ .

$x^{3} - 3 x + x \cdot 3 \cdot \frac{1}{x^{2}} + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.16.2

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

$x^{3} - 3 x + x \cdot 3 \cdot \frac{1}{x \cdot x} + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.16.3

Cancel the common factor.

$x^{3} - 3 x + x \cdot 3 \cdot \frac{1}{x \cdot x} + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.16.4

Rewrite the expression.

$x^{3} - 3 x + 3 \cdot \frac{1}{x} + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.17

Combine $3$ and $\frac{1}{x}$ .

$x^{3} - 3 x + \frac{3}{x} + 1 \cdot {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.18

Multiply ${(x)}^{0}$ by $1$ .

$x^{3} - 3 x + \frac{3}{x} + {(x)}^{0} \cdot {(- \frac{1}{x})}^{3}$

Step 4.19

Anything raised to $0$ is $1$ .

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

Step 4.20

Multiply ${(- \frac{1}{x})}^{3}$ by $1$ .

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

Step 4.21

Use the power rule ${(a b)}^{n} = a^{n} b^{n}$ to distribute the exponent.

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Step 4.21.1

Apply the product rule to $- \frac{1}{x}$ .

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

Step 4.21.2

Apply the product rule to $\frac{1}{x}$ .

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

Step 4.22

Raise $- 1$ to the power of $3$ .

$x^{3} - 3 x + \frac{3}{x} - \frac{1^{3}}{x^{3}}$

Step 4.23

One to any power is one.

$x^{3} - 3 x + \frac{3}{x} - \frac{1}{x^{3}}$