Pre-Algebra Examples

$\frac{\frac{x^{3} - 125}{x^{3} + 125}}{\frac{x^{2} - 25}{x^{2} \cdot (5 x) + 25}}$

Step 1

Multiply the numerator by the reciprocal of the denominator.

$\frac{x^{3} - 125}{x^{3} + 125} \cdot \frac{x^{2} \cdot (5 x) + 25}{x^{2} - 25}$

Step 2

Simplify the numerator.

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Step 2.1

Rewrite $125$ as $5^{3}$ .

$\frac{x^{3} - 5^{3}}{x^{3} + 125} \cdot \frac{x^{2} \cdot (5 x) + 25}{x^{2} - 25}$

Step 2.2

Since both terms are perfect cubes, factor using the difference of cubes formula, $a^{3} - b^{3} = (a - b) (a^{2} + a b + b^{2})$ where $a = x$ and $b = 5$ .

$\frac{(x - 5) (x^{2} + x \cdot 5 + 5^{2})}{x^{3} + 125} \cdot \frac{x^{2} \cdot (5 x) + 25}{x^{2} - 25}$

Step 2.3

Simplify.

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Step 2.3.1

Move $5$ to the left of $x$ .

$\frac{(x - 5) (x^{2} + 5 \cdot x + 5^{2})}{x^{3} + 125} \cdot \frac{x^{2} \cdot (5 x) + 25}{x^{2} - 25}$

Step 2.3.2

Raise $5$ to the power of $2$ .

$\frac{(x - 5) (x^{2} + 5 x + 25)}{x^{3} + 125} \cdot \frac{x^{2} \cdot (5 x) + 25}{x^{2} - 25}$

Step 3

Simplify the denominator.

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Step 3.1

Rewrite $125$ as $5^{3}$ .

$\frac{(x - 5) (x^{2} + 5 x + 25)}{x^{3} + 5^{3}} \cdot \frac{x^{2} \cdot (5 x) + 25}{x^{2} - 25}$

Step 3.2

Since both terms are perfect cubes, factor using the sum of cubes formula, $a^{3} + b^{3} = (a + b) (a^{2} - a b + b^{2})$ where $a = x$ and $b = 5$ .

$\frac{(x - 5) (x^{2} + 5 x + 25)}{(x + 5) (x^{2} - x \cdot 5 + 5^{2})} \cdot \frac{x^{2} \cdot (5 x) + 25}{x^{2} - 25}$

Step 3.3

Simplify.

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Step 3.3.1

Multiply $5$ by $- 1$ .

$\frac{(x - 5) (x^{2} + 5 x + 25)}{(x + 5) (x^{2} - 5 x + 5^{2})} \cdot \frac{x^{2} \cdot (5 x) + 25}{x^{2} - 25}$

Step 3.3.2

Raise $5$ to the power of $2$ .

$\frac{(x - 5) (x^{2} + 5 x + 25)}{(x + 5) (x^{2} - 5 x + 25)} \cdot \frac{x^{2} \cdot (5 x) + 25}{x^{2} - 25}$

Step 4

Simplify the numerator.

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Step 4.1

Factor $5$ out of $x^{2} \cdot (5 x) + 25$ .

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Step 4.1.1

Factor $5$ out of $x^{2} \cdot (5 x)$ .

$\frac{(x - 5) (x^{2} + 5 x + 25)}{(x + 5) (x^{2} - 5 x + 25)} \cdot \frac{5 (x^{2} \cdot (x)) + 25}{x^{2} - 25}$

Step 4.1.2

Factor $5$ out of $25$ .

$\frac{(x - 5) (x^{2} + 5 x + 25)}{(x + 5) (x^{2} - 5 x + 25)} \cdot \frac{5 (x^{2} \cdot (x)) + 5 \cdot 5}{x^{2} - 25}$

Step 4.1.3

Factor $5$ out of $5 (x^{2} \cdot (x)) + 5 \cdot 5$ .

$\frac{(x - 5) (x^{2} + 5 x + 25)}{(x + 5) (x^{2} - 5 x + 25)} \cdot \frac{5 (x^{2} \cdot (x) + 5)}{x^{2} - 25}$

Step 4.2

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

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Step 4.2.1

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

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Step 4.2.1.1

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

$\frac{(x - 5) (x^{2} + 5 x + 25)}{(x + 5) (x^{2} - 5 x + 25)} \cdot \frac{5 (x^{2} \cdot x^{1} + 5)}{x^{2} - 25}$

Step 4.2.1.2

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

$\frac{(x - 5) (x^{2} + 5 x + 25)}{(x + 5) (x^{2} - 5 x + 25)} \cdot \frac{5 (x^{2 + 1} + 5)}{x^{2} - 25}$

Step 4.2.2

Add $2$ and $1$ .

$\frac{(x - 5) (x^{2} + 5 x + 25)}{(x + 5) (x^{2} - 5 x + 25)} \cdot \frac{5 (x^{3} + 5)}{x^{2} - 25}$

Step 5

Simplify the denominator.

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Step 5.1

Rewrite $25$ as $5^{2}$ .

$\frac{(x - 5) (x^{2} + 5 x + 25)}{(x + 5) (x^{2} - 5 x + 25)} \cdot \frac{5 (x^{3} + 5)}{x^{2} - 5^{2}}$

Step 5.2

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 $b = 5$ .

$\frac{(x - 5) (x^{2} + 5 x + 25)}{(x + 5) (x^{2} - 5 x + 25)} \cdot \frac{5 (x^{3} + 5)}{(x + 5) (x - 5)}$

Step 6

Combine.

$\frac{(x - 5) (x^{2} + 5 x + 25) (5 (x^{3} + 5))}{(x + 5) (x^{2} - 5 x + 25) ((x + 5) (x - 5))}$

Step 7

Cancel the common factor of $x - 5$ .

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Step 7.1

Cancel the common factor.

$\frac{(x - 5) (x^{2} + 5 x + 25) (5 (x^{3} + 5))}{(x + 5) (x^{2} - 5 x + 25) ((x + 5) (x - 5))}$

Step 7.2

Rewrite the expression.

$\frac{(x^{2} + 5 x + 25) (5 (x^{3} + 5))}{(x + 5) (x^{2} - 5 x + 25) (x + 5)}$

Step 8

Simplify the denominator.

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Step 8.1

Raise $x + 5$ to the power of $1$ .

$\frac{(x^{2} + 5 x + 25) \cdot 5 (x^{3} + 5)}{{(x + 5)}^{1} (x + 5) (x^{2} - 5 x + 25)}$

Step 8.2

Raise $x + 5$ to the power of $1$ .

$\frac{(x^{2} + 5 x + 25) \cdot 5 (x^{3} + 5)}{{(x + 5)}^{1} {(x + 5)}^{1} (x^{2} - 5 x + 25)}$

Step 8.3

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

$\frac{(x^{2} + 5 x + 25) \cdot 5 (x^{3} + 5)}{{(x + 5)}^{1 + 1} (x^{2} - 5 x + 25)}$

Step 8.4

Add $1$ and $1$ .

$\frac{(x^{2} + 5 x + 25) \cdot 5 (x^{3} + 5)}{{(x + 5)}^{2} (x^{2} - 5 x + 25)}$

Step 9

Move $5$ to the left of $x^{2} + 5 x + 25$ .

$\frac{5 (x^{2} + 5 x + 25) (x^{3} + 5)}{{(x + 5)}^{2} (x^{2} - 5 x + 25)}$