Pre-Algebra Examples

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

Step 1

Simplify each term.

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Step 1.1

Factor using the perfect square rule.

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Step 1.1.1

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

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

Step 1.1.2

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 1.1.3

Rewrite the polynomial.

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

Step 1.1.4

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

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

Step 1.2

Simplify the denominator.

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Step 1.2.1

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

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

Step 1.2.2

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 $b = 2$ .

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

Step 2

To write $\frac{x + 8}{{(x - 2)}^{2}}$ as a fraction with a common denominator, multiply by $\frac{x + 2}{x + 2}$ .

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

Step 3

To write $\frac{3 x - 2}{(x + 2) (x - 2)}$ as a fraction with a common denominator, multiply by $\frac{x - 2}{x - 2}$ .

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

Step 4

Write each expression with a common denominator of $(x + 2) {(x - 2)}^{2}$ , by multiplying each by an appropriate factor of $1$ .

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Step 4.1

Multiply $\frac{x + 8}{{(x - 2)}^{2}}$ by $\frac{x + 2}{x + 2}$ .

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

Step 4.2

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

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

Step 4.3

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

$\frac{(x + 8) (x + 2)}{{(x - 2)}^{2} (x + 2)} + \frac{(3 x - 2) (x - 2)}{(x + 2) ({(x - 2)}^{1} (x - 2))}$

Step 4.4

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

$\frac{(x + 8) (x + 2)}{{(x - 2)}^{2} (x + 2)} + \frac{(3 x - 2) (x - 2)}{(x + 2) ({(x - 2)}^{1} {(x - 2)}^{1})}$

Step 4.5

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

$\frac{(x + 8) (x + 2)}{{(x - 2)}^{2} (x + 2)} + \frac{(3 x - 2) (x - 2)}{(x + 2) {(x - 2)}^{1 + 1}}$

Step 4.6

Add $1$ and $1$ .

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

Step 4.7

Reorder the factors of $(x + 2) {(x - 2)}^{2}$ .

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

Step 5

Combine the numerators over the common denominator.

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

Step 6

Simplify the numerator.

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Step 6.1

Expand $(x + 8) (x + 2)$ using the FOIL Method.

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Step 6.1.1

Apply the distributive property.

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

Step 6.1.2

Apply the distributive property.

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

Step 6.1.3

Apply the distributive property.

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

Step 6.2

Simplify and combine like terms.

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Step 6.2.1

Simplify each term.

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Step 6.2.1.1

Multiply $x$ by $x$ .

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

Step 6.2.1.2

Move $2$ to the left of $x$ .

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

Step 6.2.1.3

Multiply $8$ by $2$ .

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

Step 6.2.2

Add $2 x$ and $8 x$ .

$\frac{x^{2} + 10 x + 16 + (3 x - 2) (x - 2)}{{(x - 2)}^{2} (x + 2)}$

Step 6.3

Expand $(3 x - 2) (x - 2)$ using the FOIL Method.

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Step 6.3.1

Apply the distributive property.

$\frac{x^{2} + 10 x + 16 + 3 x (x - 2) - 2 (x - 2)}{{(x - 2)}^{2} (x + 2)}$

Step 6.3.2

Apply the distributive property.

$\frac{x^{2} + 10 x + 16 + 3 x \cdot x + 3 x \cdot - 2 - 2 (x - 2)}{{(x - 2)}^{2} (x + 2)}$

Step 6.3.3

Apply the distributive property.

$\frac{x^{2} + 10 x + 16 + 3 x \cdot x + 3 x \cdot - 2 - 2 x - 2 \cdot - 2}{{(x - 2)}^{2} (x + 2)}$

Step 6.4

Simplify and combine like terms.

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Step 6.4.1

Simplify each term.

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Step 6.4.1.1

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

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Step 6.4.1.1.1

Move $x$ .

$\frac{x^{2} + 10 x + 16 + 3 (x \cdot x) + 3 x \cdot - 2 - 2 x - 2 \cdot - 2}{{(x - 2)}^{2} (x + 2)}$

Step 6.4.1.1.2

Multiply $x$ by $x$ .

$\frac{x^{2} + 10 x + 16 + 3 x^{2} + 3 x \cdot - 2 - 2 x - 2 \cdot - 2}{{(x - 2)}^{2} (x + 2)}$

Step 6.4.1.2

Multiply $- 2$ by $3$ .

$\frac{x^{2} + 10 x + 16 + 3 x^{2} - 6 x - 2 x - 2 \cdot - 2}{{(x - 2)}^{2} (x + 2)}$

Step 6.4.1.3

Multiply $- 2$ by $- 2$ .

$\frac{x^{2} + 10 x + 16 + 3 x^{2} - 6 x - 2 x + 4}{{(x - 2)}^{2} (x + 2)}$

Step 6.4.2

Subtract $2 x$ from $- 6 x$ .

$\frac{x^{2} + 10 x + 16 + 3 x^{2} - 8 x + 4}{{(x - 2)}^{2} (x + 2)}$

Step 6.5

Add $x^{2}$ and $3 x^{2}$ .

$\frac{4 x^{2} + 10 x + 16 - 8 x + 4}{{(x - 2)}^{2} (x + 2)}$

Step 6.6

Subtract $8 x$ from $10 x$ .

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

Step 6.7

Add $16$ and $4$ .

$\frac{4 x^{2} + 2 x + 20}{{(x - 2)}^{2} (x + 2)}$

Step 6.8

Factor $2$ out of $4 x^{2} + 2 x + 20$ .

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Step 6.8.1

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

$\frac{2 (2 x^{2}) + 2 x + 20}{{(x - 2)}^{2} (x + 2)}$

Step 6.8.2

Factor $2$ out of $2 x$ .

$\frac{2 (2 x^{2}) + 2 (x) + 20}{{(x - 2)}^{2} (x + 2)}$

Step 6.8.3

Factor $2$ out of $20$ .

$\frac{2 (2 x^{2}) + 2 x + 2 \cdot 10}{{(x - 2)}^{2} (x + 2)}$

Step 6.8.4

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

$\frac{2 (2 x^{2} + x) + 2 \cdot 10}{{(x - 2)}^{2} (x + 2)}$

Step 6.8.5

Factor $2$ out of $2 (2 x^{2} + x) + 2 \cdot 10$ .

$\frac{2 (2 x^{2} + x + 10)}{{(x - 2)}^{2} (x + 2)}$