Precalculus Examples

$\frac{3 x + 1}{2 x^{2} - 2} + \frac{2 x + 2}{2 x^{2} - 8 x + 6}$

Step 1

Simplify each term.

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Step 1.1

Simplify the denominator.

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Step 1.1.1

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

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Step 1.1.1.1

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

$\frac{3 x + 1}{2 (x^{2}) - 2} + \frac{2 x + 2}{2 x^{2} - 8 x + 6}$

Step 1.1.1.2

Factor $2$ out of $- 2$ .

$\frac{3 x + 1}{2 (x^{2}) + 2 (- 1)} + \frac{2 x + 2}{2 x^{2} - 8 x + 6}$

Step 1.1.1.3

Factor $2$ out of $2 (x^{2}) + 2 (- 1)$ .

$\frac{3 x + 1}{2 (x^{2} - 1)} + \frac{2 x + 2}{2 x^{2} - 8 x + 6}$

Step 1.1.2

Rewrite $1$ as $1^{2}$ .

$\frac{3 x + 1}{2 (x^{2} - 1^{2})} + \frac{2 x + 2}{2 x^{2} - 8 x + 6}$

Step 1.1.3

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 $b = 1$ .

$\frac{3 x + 1}{2 (x + 1) (x - 1)} + \frac{2 x + 2}{2 x^{2} - 8 x + 6}$

Step 1.2

Cancel the common factor of $2 x + 2$ and $2 x^{2} - 8 x + 6$ .

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Step 1.2.1

Factor $2$ out of $2 x$ .

$\frac{3 x + 1}{2 (x + 1) (x - 1)} + \frac{2 (x) + 2}{2 x^{2} - 8 x + 6}$

Step 1.2.2

Factor $2$ out of $2$ .

$\frac{3 x + 1}{2 (x + 1) (x - 1)} + \frac{2 (x) + 2 \cdot 1}{2 x^{2} - 8 x + 6}$

Step 1.2.3

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

$\frac{3 x + 1}{2 (x + 1) (x - 1)} + \frac{2 (x + 1)}{2 x^{2} - 8 x + 6}$

Step 1.2.4

Cancel the common factors.

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Step 1.2.4.1

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

$\frac{3 x + 1}{2 (x + 1) (x - 1)} + \frac{2 (x + 1)}{2 (x^{2}) - 8 x + 6}$

Step 1.2.4.2

Factor $2$ out of $- 8 x$ .

$\frac{3 x + 1}{2 (x + 1) (x - 1)} + \frac{2 (x + 1)}{2 (x^{2}) + 2 (- 4 x) + 6}$

Step 1.2.4.3

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

$\frac{3 x + 1}{2 (x + 1) (x - 1)} + \frac{2 (x + 1)}{2 (x^{2} - 4 x) + 6}$

Step 1.2.4.4

Factor $2$ out of $6$ .

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

Step 1.2.4.5

Factor $2$ out of $2 (x^{2} - 4 x) + 2 \cdot 3$ .

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

Step 1.2.4.6

Cancel the common factor.

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

Step 1.2.4.7

Rewrite the expression.

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

Step 1.3

Factor $x^{2} - 4 x + 3$ using the AC method.

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Step 1.3.1

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 $3$ and whose sum is $- 4$ .

$- 3, - 1$

Step 1.3.2

Write the factored form using these integers.

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

Step 2

To write $\frac{3 x + 1}{2 (x + 1) (x - 1)}$ as a fraction with a common denominator, multiply by $\frac{x - 3}{x - 3}$ .

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

Step 3

To write $\frac{x + 1}{(x - 3) (x - 1)}$ as a fraction with a common denominator, multiply by $\frac{2 (x + 1)}{2 (x + 1)}$ .

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

Step 4

Write each expression with a common denominator of $2 (x + 1) (x - 1) (x - 3)$ , by multiplying each by an appropriate factor of $1$ .

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Step 4.1

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

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

Step 4.2

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

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

Step 4.3

Reorder the factors of $(x - 3) (x - 1) (2 (x + 1))$ .

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

Step 5

Combine the numerators over the common denominator.

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

Step 6

Simplify the numerator.

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Step 6.1

Expand $(3 x + 1) (x - 3)$ using the FOIL Method.

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Step 6.1.1

Apply the distributive property.

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

Step 6.1.2

Apply the distributive property.

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

Step 6.1.3

Apply the distributive property.

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

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 $x$ by adding the exponents.

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Step 6.2.1.1.1

Move $x$ .

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

Step 6.2.1.1.2

Multiply $x$ by $x$ .

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

Step 6.2.1.2

Multiply $- 3$ by $3$ .

$\frac{3 x^{2} - 9 x + 1 x + 1 \cdot - 3 + (x + 1) \cdot 2 (x + 1)}{2 (x + 1) (x - 1) (x - 3)}$

Step 6.2.1.3

Multiply $x$ by $1$ .

$\frac{3 x^{2} - 9 x + x + 1 \cdot - 3 + (x + 1) \cdot 2 (x + 1)}{2 (x + 1) (x - 1) (x - 3)}$

Step 6.2.1.4

Multiply $- 3$ by $1$ .

$\frac{3 x^{2} - 9 x + x - 3 + (x + 1) \cdot 2 (x + 1)}{2 (x + 1) (x - 1) (x - 3)}$

Step 6.2.2

Add $- 9 x$ and $x$ .

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

Step 6.3

Apply the distributive property.

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

Step 6.4

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

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

Step 6.5

Multiply $2$ by $1$ .

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

Step 6.6

Expand $(2 x + 2) (x + 1)$ using the FOIL Method.

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Step 6.6.1

Apply the distributive property.

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

Step 6.6.2

Apply the distributive property.

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

Step 6.6.3

Apply the distributive property.

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

Step 6.7

Simplify and combine like terms.

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Step 6.7.1

Simplify each term.

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Step 6.7.1.1

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

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Step 6.7.1.1.1

Move $x$ .

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

Step 6.7.1.1.2

Multiply $x$ by $x$ .

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

Step 6.7.1.2

Multiply $2$ by $1$ .

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

Step 6.7.1.3

Multiply $2$ by $1$ .

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

Step 6.7.2

Add $2 x$ and $2 x$ .

$\frac{3 x^{2} - 8 x - 3 + 2 x^{2} + 4 x + 2}{2 (x + 1) (x - 1) (x - 3)}$

Step 6.8

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

$\frac{5 x^{2} - 8 x - 3 + 4 x + 2}{2 (x + 1) (x - 1) (x - 3)}$

Step 6.9

Add $- 8 x$ and $4 x$ .

$\frac{5 x^{2} - 4 x - 3 + 2}{2 (x + 1) (x - 1) (x - 3)}$

Step 6.10

Add $- 3$ and $2$ .

$\frac{5 x^{2} - 4 x - 1}{2 (x + 1) (x - 1) (x - 3)}$

Step 6.11

Factor by grouping.

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Step 6.11.1

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 $a \cdot c = 5 \cdot - 1 = - 5$ and whose sum is $b = - 4$ .

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Step 6.11.1.1

Factor $- 4$ out of $- 4 x$ .

$\frac{5 x^{2} - 4 (x) - 1}{2 (x + 1) (x - 1) (x - 3)}$

Step 6.11.1.2

Rewrite $- 4$ as $1$ plus $- 5$

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

Step 6.11.1.3

Apply the distributive property.

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

Step 6.11.1.4

Multiply $x$ by $1$ .

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

Step 6.11.2

Factor out the greatest common factor from each group.

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Step 6.11.2.1

Group the first two terms and the last two terms.

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

Step 6.11.2.2

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

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

Step 6.11.3

Factor the polynomial by factoring out the greatest common factor, $5 x + 1$ .

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

Step 7

Cancel the common factor of $x - 1$ .

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Step 7.1

Cancel the common factor.

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

Step 7.2

Rewrite the expression.

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