Calculus Examples

$\frac{2 x}{x^{2} - 6 x + 9} - \frac{1}{x + 1} - \frac{8}{x^{2} - 2 x - 3}$

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 $9$ as $3^{2}$ .

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

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.

$6 x = 2 \cdot x \cdot 3$

Step 1.1.3

Rewrite the polynomial.

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

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 $b = 3$ .

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

Step 1.2

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

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Step 1.2.1

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 $- 3$ and whose sum is $- 2$ .

$- 3, 1$

Step 1.2.2

Write the factored form using these integers.

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

Step 2

Find the common denominator.

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Step 2.1

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

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

Step 2.2

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

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

Step 2.3

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

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

Step 2.4

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

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

Step 2.5

Multiply $\frac{8}{(x - 3) (x + 1)}$ by $\frac{x - 3}{x - 3}$ .

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

Step 2.6

Multiply $\frac{8}{(x - 3) (x + 1)}$ by $\frac{x - 3}{x - 3}$ .

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

Step 2.7

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

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

Step 2.8

Raise $x - 3$ to the power of $1$ .

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

Step 2.9

Raise $x - 3$ to the power of $1$ .

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

Step 2.10

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

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

Step 2.11

Add $1$ and $1$ .

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

Step 3

Combine the numerators over the common denominator.

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

Step 4

Simplify each term.

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Step 4.1

Apply the distributive property.

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

Step 4.2

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

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Step 4.2.1

Move $x$ .

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

Step 4.2.2

Multiply $x$ by $x$ .

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

Step 4.3

Multiply $2$ by $1$ .

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

Step 4.4

Rewrite ${(x - 3)}^{2}$ as $(x - 3) (x - 3)$ .

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

Step 4.5

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

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Step 4.5.1

Apply the distributive property.

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

Step 4.5.2

Apply the distributive property.

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

Step 4.5.3

Apply the distributive property.

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

Step 4.6

Simplify and combine like terms.

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Step 4.6.1

Simplify each term.

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Step 4.6.1.1

Multiply $x$ by $x$ .

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

Step 4.6.1.2

Move $- 3$ to the left of $x$ .

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

Step 4.6.1.3

Multiply $- 3$ by $- 3$ .

$\frac{2 x^{2} + 2 x - (x^{2} - 3 x - 3 x + 9) - 8 (x - 3)}{{(x - 3)}^{2} (x + 1)}$

Step 4.6.2

Subtract $3 x$ from $- 3 x$ .

$\frac{2 x^{2} + 2 x - (x^{2} - 6 x + 9) - 8 (x - 3)}{{(x - 3)}^{2} (x + 1)}$

Step 4.7

Apply the distributive property.

$\frac{2 x^{2} + 2 x - x^{2} - (- 6 x) - 1 \cdot 9 - 8 (x - 3)}{{(x - 3)}^{2} (x + 1)}$

Step 4.8

Simplify.

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Step 4.8.1

Multiply $- 6$ by $- 1$ .

$\frac{2 x^{2} + 2 x - x^{2} + 6 x - 1 \cdot 9 - 8 (x - 3)}{{(x - 3)}^{2} (x + 1)}$

Step 4.8.2

Multiply $- 1$ by $9$ .

$\frac{2 x^{2} + 2 x - x^{2} + 6 x - 9 - 8 (x - 3)}{{(x - 3)}^{2} (x + 1)}$

Step 4.9

Apply the distributive property.

$\frac{2 x^{2} + 2 x - x^{2} + 6 x - 9 - 8 x - 8 \cdot - 3}{{(x - 3)}^{2} (x + 1)}$

Step 4.10

Multiply $- 8$ by $- 3$ .

$\frac{2 x^{2} + 2 x - x^{2} + 6 x - 9 - 8 x + 24}{{(x - 3)}^{2} (x + 1)}$

Step 5

Simplify by adding terms.

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Step 5.1

Subtract $x^{2}$ from $2 x^{2}$ .

$\frac{x^{2} + 2 x + 6 x - 9 - 8 x + 24}{{(x - 3)}^{2} (x + 1)}$

Step 5.2

Add $2 x$ and $6 x$ .

$\frac{x^{2} + 8 x - 9 - 8 x + 24}{{(x - 3)}^{2} (x + 1)}$

Step 5.3

Combine the opposite terms in $x^{2} + 8 x - 9 - 8 x + 24$ .

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Step 5.3.1

Subtract $8 x$ from $8 x$ .

$\frac{x^{2} + 0 - 9 + 24}{{(x - 3)}^{2} (x + 1)}$

Step 5.3.2

Add $x^{2}$ and $0$ .

$\frac{x^{2} - 9 + 24}{{(x - 3)}^{2} (x + 1)}$

Step 5.4

Add $- 9$ and $24$ .

$\frac{x^{2} + 15}{{(x - 3)}^{2} (x + 1)}$