Finite Math Examples

$\frac{\frac{x^{3} - 2 x^{2} - 8 x}{3 x (x^{2} - 16)}}{\frac{x^{2} + 4 x + 4}{9 x^{2}}}$

Step 1

Multiply the numerator by the reciprocal of the denominator.

$\frac{x^{3} - 2 x^{2} - 8 x}{3 x (x^{2} - 16)} \cdot \frac{9 x^{2}}{x^{2} + 4 x + 4}$

Step 2

Simplify terms.

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Step 2.1

Cancel the common factor of $3 x$ .

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Step 2.1.1

Factor $3 x$ out of $9 x^{2}$ .

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

Step 2.1.2

Cancel the common factor.

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

Step 2.1.3

Rewrite the expression.

$\frac{x^{3} - 2 x^{2} - 8 x}{x^{2} - 16} \cdot \frac{3 x}{x^{2} + 4 x + 4}$

Step 2.2

Multiply $\frac{x^{3} - 2 x^{2} - 8 x}{x^{2} - 16}$ by $\frac{3 x}{x^{2} + 4 x + 4}$ .

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

Step 3

Simplify the numerator.

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Step 3.1

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

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Step 3.1.1

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

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

Step 3.1.2

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

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

Step 3.1.3

Factor $x$ out of $- 8 x$ .

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

Step 3.1.4

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

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

Step 3.1.5

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

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

Step 3.2

Factor $x^{2} - 2 x - 8$ using the AC method.

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Step 3.2.1

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 $- 8$ and whose sum is $- 2$ .

$- 4, 2$

Step 3.2.2

Write the factored form using these integers.

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

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

Step 3.3

Combine exponents.

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Step 3.3.1

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

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

Step 3.3.2

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

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

Step 3.3.3

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

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

Step 3.3.4

Add $1$ and $1$ .

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

Step 4

Simplify the denominator.

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Step 4.1

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

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

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 $a = x$ and $b = 4$ .

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

Step 4.3

Factor using the perfect square rule.

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Step 4.3.1

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

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

Step 4.3.2

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

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

Step 4.3.3

Rewrite the polynomial.

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

Step 4.3.4

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

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

Step 5

Reduce the expression by cancelling the common factors.

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Step 5.1

Cancel the common factor of $x - 4$ .

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Step 5.1.1

Cancel the common factor.

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

Step 5.1.2

Rewrite the expression.

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

Step 5.2

Cancel the common factor of $x + 2$ and ${(x + 2)}^{2}$ .

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Step 5.2.1

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

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

Step 5.2.2

Cancel the common factors.

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Step 5.2.2.1

Factor $x + 2$ out of $(x + 4) {(x + 2)}^{2}$ .

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

Step 5.2.2.2

Cancel the common factor.

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

Step 5.2.2.3

Rewrite the expression.

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

Step 5.3

Move $3$ to the left of $x^{2}$ .

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