Algebra Examples

$\frac{x^{2} - 16}{2 x^{2} - 9 x + 4} \div \frac{2 x^{2} + 14 x + 24}{4 x + 4}$

Step 1

To divide by a fraction, multiply by its reciprocal.

$\frac{x^{2} - 16}{2 x^{2} - 9 x + 4} \cdot \frac{4 x + 4}{2 x^{2} + 14 x + 24}$

Step 2

Simplify the numerator.

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Step 2.1

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

$\frac{x^{2} - 4^{2}}{2 x^{2} - 9 x + 4} \cdot \frac{4 x + 4}{2 x^{2} + 14 x + 24}$

Step 2.2

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 $b = 4$ .

$\frac{(x + 4) (x - 4)}{2 x^{2} - 9 x + 4} \cdot \frac{4 x + 4}{2 x^{2} + 14 x + 24}$

Step 3

Factor by grouping.

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Step 3.1

For a polynomial of the form $a x^{2} + b x + c$ , rewrite the middle term as a sum of two terms whose product is $a \cdot c = 2 \cdot 4 = 8$ and whose sum is $b = - 9$ .

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Step 3.1.1

Factor $- 9$ out of $- 9 x$ .

$\frac{(x + 4) (x - 4)}{2 x^{2} - 9 (x) + 4} \cdot \frac{4 x + 4}{2 x^{2} + 14 x + 24}$

Step 3.1.2

Rewrite $- 9$ as $- 1$ plus $- 8$

$\frac{(x + 4) (x - 4)}{2 x^{2} + (- 1 - 8) x + 4} \cdot \frac{4 x + 4}{2 x^{2} + 14 x + 24}$

Step 3.1.3

Apply the distributive property.

$\frac{(x + 4) (x - 4)}{2 x^{2} - 1 x - 8 x + 4} \cdot \frac{4 x + 4}{2 x^{2} + 14 x + 24}$

Step 3.2

Factor out the greatest common factor from each group.

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Step 3.2.1

Group the first two terms and the last two terms.

$\frac{(x + 4) (x - 4)}{(2 x^{2} - 1 x) - 8 x + 4} \cdot \frac{4 x + 4}{2 x^{2} + 14 x + 24}$

Step 3.2.2

Factor out the greatest common factor (GCF) from each group.

$\frac{(x + 4) (x - 4)}{x (2 x - 1) - 4 (2 x - 1)} \cdot \frac{4 x + 4}{2 x^{2} + 14 x + 24}$

Step 3.3

Factor the polynomial by factoring out the greatest common factor, $2 x - 1$ .

$\frac{(x + 4) (x - 4)}{(2 x - 1) (x - 4)} \cdot \frac{4 x + 4}{2 x^{2} + 14 x + 24}$

Step 4

Cancel the common factor of $x - 4$ .

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Step 4.1

Cancel the common factor.

$\frac{(x + 4) (x - 4)}{(2 x - 1) (x - 4)} \cdot \frac{4 x + 4}{2 x^{2} + 14 x + 24}$

Step 4.2

Rewrite the expression.

$\frac{x + 4}{2 x - 1} \cdot \frac{4 x + 4}{2 x^{2} + 14 x + 24}$

Step 5

Cancel the common factor of $4 x + 4$ and $2 x^{2} + 14 x + 24$ .

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Step 5.1

Factor $2$ out of $4 x$ .

$\frac{x + 4}{2 x - 1} \cdot \frac{2 (2 x) + 4}{2 x^{2} + 14 x + 24}$

Step 5.2

Factor $2$ out of $4$ .

$\frac{x + 4}{2 x - 1} \cdot \frac{2 (2 x) + 2 \cdot 2}{2 x^{2} + 14 x + 24}$

Step 5.3

Factor $2$ out of $2 (2 x) + 2 (2)$ .

$\frac{x + 4}{2 x - 1} \cdot \frac{2 (2 x + 2)}{2 x^{2} + 14 x + 24}$

Step 5.4

Cancel the common factors.

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Step 5.4.1

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

$\frac{x + 4}{2 x - 1} \cdot \frac{2 (2 x + 2)}{2 (x^{2}) + 14 x + 24}$

Step 5.4.2

Factor $2$ out of $14 x$ .

$\frac{x + 4}{2 x - 1} \cdot \frac{2 (2 x + 2)}{2 (x^{2}) + 2 (7 x) + 24}$

Step 5.4.3

Factor $2$ out of $2 (x^{2}) + 2 (7 x)$ .

$\frac{x + 4}{2 x - 1} \cdot \frac{2 (2 x + 2)}{2 (x^{2} + 7 x) + 24}$

Step 5.4.4

Factor $2$ out of $24$ .

$\frac{x + 4}{2 x - 1} \cdot \frac{2 (2 x + 2)}{2 (x^{2} + 7 x) + 2 \cdot 12}$

Step 5.4.5

Factor $2$ out of $2 (x^{2} + 7 x) + 2 \cdot 12$ .

$\frac{x + 4}{2 x - 1} \cdot \frac{2 (2 x + 2)}{2 (x^{2} + 7 x + 12)}$

Step 5.4.6

Cancel the common factor.

$\frac{x + 4}{2 x - 1} \cdot \frac{2 (2 x + 2)}{2 (x^{2} + 7 x + 12)}$

Step 5.4.7

Rewrite the expression.

$\frac{x + 4}{2 x - 1} \cdot \frac{2 x + 2}{x^{2} + 7 x + 12}$

Step 6

Factor $2$ out of $2 x + 2$ .

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Step 6.1

Factor $2$ out of $2 x$ .

$\frac{x + 4}{2 x - 1} \cdot \frac{2 (x) + 2}{x^{2} + 7 x + 12}$

Step 6.2

Factor $2$ out of $2$ .

$\frac{x + 4}{2 x - 1} \cdot \frac{2 (x) + 2 (1)}{x^{2} + 7 x + 12}$

Step 6.3

Factor $2$ out of $2 (x) + 2 (1)$ .

$\frac{x + 4}{2 x - 1} \cdot \frac{2 (x + 1)}{x^{2} + 7 x + 12}$

Step 7

Factor $x^{2} + 7 x + 12$ using the AC method.

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Step 7.1

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 $12$ and whose sum is $7$ .

$3, 4$

Step 7.2

Write the factored form using these integers.

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

Step 8

Cancel the common factor of $x + 4$ .

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Step 8.1

Factor $x + 4$ out of $(x + 3) (x + 4)$ .

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

Step 8.2

Cancel the common factor.

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

Step 8.3

Rewrite the expression.

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

Step 9

Multiply $\frac{1}{2 x - 1}$ by $\frac{2 (x + 1)}{x + 3}$ .

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

Step 10

Apply the distributive property.

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

Step 11

Multiply $2$ by $1$ .

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

Step 12

Split the fraction $\frac{2 x + 2}{(2 x - 1) (x + 3)}$ into two fractions.

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