Algebra Examples

$f (x) = x^{6} - 6 x^{4} - 31 x^{2} + 36$

Step 1

Factor $x^{6} - 6 x^{4} - 31 x^{2} + 36$ using the rational roots test.

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Step 1.1

If a polynomial function has integer coefficients, then every rational zero will have the form $\frac{p}{q}$ where $p$ is a factor of the constant and $q$ is a factor of the leading coefficient.

$p = \pm 1, \pm 36, \pm 2, \pm 18, \pm 3, \pm 12, \pm 4, \pm 9, \pm 6$

$q = \pm 1$

Step 1.2

Find every combination of $\pm \frac{p}{q}$ . These are the possible roots of the polynomial function.

$\pm 1, \pm 36, \pm 2, \pm 18, \pm 3, \pm 12, \pm 4, \pm 9, \pm 6$

Step 1.3

Substitute $- 1$ and simplify the expression. In this case, the expression is equal to $0$ so $- 1$ is a root of the polynomial.

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Step 1.3.1

Substitute $- 1$ into the polynomial.

${(- 1)}^{6} - 6 {(- 1)}^{4} - 31 {(- 1)}^{2} + 36$

Step 1.3.2

Raise $- 1$ to the power of $6$ .

$1 - 6 {(- 1)}^{4} - 31 {(- 1)}^{2} + 36$

Step 1.3.3

Raise $- 1$ to the power of $4$ .

$1 - 6 \cdot 1 - 31 {(- 1)}^{2} + 36$

Step 1.3.4

Multiply $- 6$ by $1$ .

$1 - 6 - 31 {(- 1)}^{2} + 36$

Step 1.3.5

Subtract $6$ from $1$ .

$- 5 - 31 {(- 1)}^{2} + 36$

Step 1.3.6

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

$- 5 - 31 \cdot 1 + 36$

Step 1.3.7

Multiply $- 31$ by $1$ .

$- 5 - 31 + 36$

Step 1.3.8

Subtract $31$ from $- 5$ .

$- 36 + 36$

Step 1.3.9

Add $- 36$ and $36$ .

$0$

Step 1.4

Since $- 1$ is a known root, divide the polynomial by $x + 1$ to find the quotient polynomial. This polynomial can then be used to find the remaining roots.

$\frac{x^{6} - 6 x^{4} - 31 x^{2} + 36}{x + 1}$

Step 1.5

Divide $x^{6} - 6 x^{4} - 31 x^{2} + 36$ by $x + 1$ .

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Step 1.5.1

Set up the polynomials to be divided. If there is not a term for every exponent, insert one with a value of $0$ .

$x$

$1$

$x^{6}$

$0 x^{5}$

$6 x^{4}$

$0 x^{3}$

$31 x^{2}$

$0 x$

$36$

Step 1.5.2

Divide the highest order term in the dividend $x^{6}$ by the highest order term in divisor $x$ .

$x^{5}$

$x$

$1$

$x^{6}$

$0 x^{5}$

$6 x^{4}$

$0 x^{3}$

$31 x^{2}$

$0 x$

$36$

Step 1.5.3

Multiply the new quotient term by the divisor.

$x^{5}$

$x$

$1$

$x^{6}$

$0 x^{5}$

$6 x^{4}$

$0 x^{3}$

$31 x^{2}$

$0 x$

$36$

$x^{6}$

$x^{5}$

Step 1.5.4

The expression needs to be subtracted from the dividend, so change all the signs in $x^{6} + x^{5}$

$x^{5}$

$x$

$1$

$x^{6}$

$0 x^{5}$

$6 x^{4}$

$0 x^{3}$

$31 x^{2}$

$0 x$

$36$

$x^{6}$

$x^{5}$

Step 1.5.5

After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.

$x^{5}$

$x$

$1$

$x^{6}$

$0 x^{5}$

$6 x^{4}$

$0 x^{3}$

$31 x^{2}$

$0 x$

$36$

$x^{6}$

$x^{5}$

Step 1.5.6

Pull the next terms from the original dividend down into the current dividend.

$x^{5}$

$x$

$1$

$x^{6}$

$0 x^{5}$

$6 x^{4}$

$0 x^{3}$

$31 x^{2}$

$0 x$

$36$

$x^{6}$

$x^{5}$

$6 x^{4}$

Step 1.5.7

Divide the highest order term in the dividend $- x^{5}$ by the highest order term in divisor $x$ .

$x^{5}$

$x^{4}$

$x$

$1$

$x^{6}$

$0 x^{5}$

$6 x^{4}$

$0 x^{3}$

$31 x^{2}$

$0 x$

$36$

$x^{6}$

$x^{5}$

$6 x^{4}$

Step 1.5.8

Multiply the new quotient term by the divisor.

$x^{5}$

$x^{4}$

$x$

$1$

$x^{6}$

$0 x^{5}$

$6 x^{4}$

$0 x^{3}$

$31 x^{2}$

$0 x$

$36$

$x^{6}$

$x^{5}$

$6 x^{4}$

$x^{5}$

$x^{4}$

Step 1.5.9

The expression needs to be subtracted from the dividend, so change all the signs in $- x^{5} - x^{4}$

$x^{5}$

$x^{4}$

$x$

$1$

$x^{6}$

$0 x^{5}$

$6 x^{4}$

$0 x^{3}$

$31 x^{2}$

$0 x$

$36$

$x^{6}$

$x^{5}$

$6 x^{4}$

$x^{5}$

$x^{4}$

Step 1.5.10

After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.

$x^{5}$

$x^{4}$

$x$

$1$

$x^{6}$

$0 x^{5}$

$6 x^{4}$

$0 x^{3}$

$31 x^{2}$

$0 x$

$36$

$x^{6}$

$x^{5}$

$6 x^{4}$

$x^{5}$

$x^{4}$

$5 x^{4}$

Step 1.5.11

Pull the next terms from the original dividend down into the current dividend.

$x^{5}$

$x^{4}$

$x$

$1$

$x^{6}$

$0 x^{5}$

$6 x^{4}$

$0 x^{3}$

$31 x^{2}$

$0 x$

$36$

$x^{6}$

$x^{5}$

$6 x^{4}$

$x^{5}$

$x^{4}$

$5 x^{4}$

$0 x^{3}$

Step 1.5.12

Divide the highest order term in the dividend $- 5 x^{4}$ by the highest order term in divisor $x$ .

$x^{5}$

$x^{4}$

$5 x^{3}$

$x$

$1$

$x^{6}$

$0 x^{5}$

$6 x^{4}$

$0 x^{3}$

$31 x^{2}$

$0 x$

$36$

$x^{6}$

$x^{5}$

$6 x^{4}$

$x^{5}$

$x^{4}$

$5 x^{4}$

$0 x^{3}$

Step 1.5.13

Multiply the new quotient term by the divisor.

$x^{5}$

$x^{4}$

$5 x^{3}$

$x$

$1$

$x^{6}$

$0 x^{5}$

$6 x^{4}$

$0 x^{3}$

$31 x^{2}$

$0 x$

$36$

$x^{6}$

$x^{5}$

$6 x^{4}$

$x^{5}$

$x^{4}$

$5 x^{4}$

$0 x^{3}$

$5 x^{4}$

$5 x^{3}$

Step 1.5.14

The expression needs to be subtracted from the dividend, so change all the signs in $- 5 x^{4} - 5 x^{3}$

$x^{5}$

$x^{4}$

$5 x^{3}$

$x$

$1$

$x^{6}$

$0 x^{5}$

$6 x^{4}$

$0 x^{3}$

$31 x^{2}$

$0 x$

$36$

$x^{6}$

$x^{5}$

$6 x^{4}$

$x^{5}$

$x^{4}$

$5 x^{4}$

$0 x^{3}$

$5 x^{4}$

$5 x^{3}$

Step 1.5.15

After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.

$x^{5}$

$x^{4}$

$5 x^{3}$

$x$

$1$

$x^{6}$

$0 x^{5}$

$6 x^{4}$

$0 x^{3}$

$31 x^{2}$

$0 x$

$36$

$x^{6}$

$x^{5}$

$6 x^{4}$

$x^{5}$

$x^{4}$

$5 x^{4}$

$0 x^{3}$

$5 x^{4}$

$5 x^{3}$

Step 1.5.16

Pull the next terms from the original dividend down into the current dividend.

$x^{5}$

$x^{4}$

$5 x^{3}$

$x$

$1$

$x^{6}$

$0 x^{5}$

$6 x^{4}$

$0 x^{3}$

$31 x^{2}$

$0 x$

$36$

$x^{6}$

$x^{5}$

$6 x^{4}$

$x^{5}$

$x^{4}$

$5 x^{4}$

$0 x^{3}$

$5 x^{4}$

$5 x^{3}$

$31 x^{2}$

Step 1.5.17

Divide the highest order term in the dividend $5 x^{3}$ by the highest order term in divisor $x$ .

$x^{5}$

$x^{4}$

$5 x^{3}$

$5 x^{2}$

$x$

$1$

$x^{6}$

$0 x^{5}$

$6 x^{4}$

$0 x^{3}$

$31 x^{2}$

$0 x$

$36$

$x^{6}$

$x^{5}$

$6 x^{4}$

$x^{5}$

$x^{4}$

$5 x^{4}$

$0 x^{3}$

$5 x^{4}$

$5 x^{3}$

$31 x^{2}$

Step 1.5.18

Multiply the new quotient term by the divisor.

$x^{5}$

$x^{4}$

$5 x^{3}$

$5 x^{2}$

$x$

$1$

$x^{6}$

$0 x^{5}$

$6 x^{4}$

$0 x^{3}$

$31 x^{2}$

$0 x$

$36$

$x^{6}$

$x^{5}$

$6 x^{4}$

$x^{5}$

$x^{4}$

$5 x^{4}$

$0 x^{3}$

$5 x^{4}$

$5 x^{3}$

$31 x^{2}$

$5 x^{3}$

$5 x^{2}$

Step 1.5.19

The expression needs to be subtracted from the dividend, so change all the signs in $5 x^{3} + 5 x^{2}$

$x^{5}$

$x^{4}$

$5 x^{3}$

$5 x^{2}$

$x$

$1$

$x^{6}$

$0 x^{5}$

$6 x^{4}$

$0 x^{3}$

$31 x^{2}$

$0 x$

$36$

$x^{6}$

$x^{5}$

$6 x^{4}$

$x^{5}$

$x^{4}$

$5 x^{4}$

$0 x^{3}$

$5 x^{4}$

$5 x^{3}$

$31 x^{2}$

$5 x^{3}$

$5 x^{2}$

Step 1.5.20

After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.

$x^{5}$

$x^{4}$

$5 x^{3}$

$5 x^{2}$

$x$

$1$

$x^{6}$

$0 x^{5}$

$6 x^{4}$

$0 x^{3}$

$31 x^{2}$

$0 x$

$36$

$x^{6}$

$x^{5}$

$6 x^{4}$

$x^{5}$

$x^{4}$

$5 x^{4}$

$0 x^{3}$

$5 x^{4}$

$5 x^{3}$

$31 x^{2}$

$5 x^{3}$

$5 x^{2}$

$36 x^{2}$

Step 1.5.21

Pull the next terms from the original dividend down into the current dividend.

$x^{5}$

$x^{4}$

$5 x^{3}$

$5 x^{2}$

$x$

$1$

$x^{6}$

$0 x^{5}$

$6 x^{4}$

$0 x^{3}$

$31 x^{2}$

$0 x$

$36$

$x^{6}$

$x^{5}$

$6 x^{4}$

$x^{5}$

$x^{4}$

$5 x^{4}$

$0 x^{3}$

$5 x^{4}$

$5 x^{3}$

$31 x^{2}$

$5 x^{3}$

$5 x^{2}$

$36 x^{2}$

$0 x$

Step 1.5.22

Divide the highest order term in the dividend $- 36 x^{2}$ by the highest order term in divisor $x$ .

$x^{5}$

$x^{4}$

$5 x^{3}$

$5 x^{2}$

$36 x$

$x$

$1$

$x^{6}$

$0 x^{5}$

$6 x^{4}$

$0 x^{3}$

$31 x^{2}$

$0 x$

$36$

$x^{6}$

$x^{5}$

$6 x^{4}$

$x^{5}$

$x^{4}$

$5 x^{4}$

$0 x^{3}$

$5 x^{4}$

$5 x^{3}$

$31 x^{2}$

$5 x^{3}$

$5 x^{2}$

$36 x^{2}$

$0 x$

Step 1.5.23

Multiply the new quotient term by the divisor.

$x^{5}$

$x^{4}$

$5 x^{3}$

$5 x^{2}$

$36 x$

$x$

$1$

$x^{6}$

$0 x^{5}$

$6 x^{4}$

$0 x^{3}$

$31 x^{2}$

$0 x$

$36$

$x^{6}$

$x^{5}$

$6 x^{4}$

$x^{5}$

$x^{4}$

$5 x^{4}$

$0 x^{3}$

$5 x^{4}$

$5 x^{3}$

$31 x^{2}$

$5 x^{3}$

$5 x^{2}$

$36 x^{2}$

$0 x$

$36 x^{2}$

$36 x$

Step 1.5.24

The expression needs to be subtracted from the dividend, so change all the signs in $- 36 x^{2} - 36 x$

$x^{5}$

$x^{4}$

$5 x^{3}$

$5 x^{2}$

$36 x$

$x$

$1$

$x^{6}$

$0 x^{5}$

$6 x^{4}$

$0 x^{3}$

$31 x^{2}$

$0 x$

$36$

$x^{6}$

$x^{5}$

$6 x^{4}$

$x^{5}$

$x^{4}$

$5 x^{4}$

$0 x^{3}$

$5 x^{4}$

$5 x^{3}$

$31 x^{2}$

$5 x^{3}$

$5 x^{2}$

$36 x^{2}$

$0 x$

$36 x^{2}$

$36 x$

Step 1.5.25

After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.

$x^{5}$

$x^{4}$

$5 x^{3}$

$5 x^{2}$

$36 x$

$x$

$1$

$x^{6}$

$0 x^{5}$

$6 x^{4}$

$0 x^{3}$

$31 x^{2}$

$0 x$

$36$

$x^{6}$

$x^{5}$

$6 x^{4}$

$x^{5}$

$x^{4}$

$5 x^{4}$

$0 x^{3}$

$5 x^{4}$

$5 x^{3}$

$31 x^{2}$

$5 x^{3}$

$5 x^{2}$

$36 x^{2}$

$0 x$

$36 x^{2}$

$36 x$

Step 1.5.26

Pull the next terms from the original dividend down into the current dividend.

$x^{5}$

$x^{4}$

$5 x^{3}$

$5 x^{2}$

$36 x$

$x$

$1$

$x^{6}$

$0 x^{5}$

$6 x^{4}$

$0 x^{3}$

$31 x^{2}$

$0 x$

$36$

$x^{6}$

$x^{5}$

$6 x^{4}$

$x^{5}$

$x^{4}$

$5 x^{4}$

$0 x^{3}$

$5 x^{4}$

$5 x^{3}$

$31 x^{2}$

$5 x^{3}$

$5 x^{2}$

$36 x^{2}$

$0 x$

$36 x^{2}$

$36 x$

$36$

Step 1.5.27

Divide the highest order term in the dividend $36 x$ by the highest order term in divisor $x$ .

$x^{5}$

$x^{4}$

$5 x^{3}$

$5 x^{2}$

$36 x$

$36$

$x$

$1$

$x^{6}$

$0 x^{5}$

$6 x^{4}$

$0 x^{3}$

$31 x^{2}$

$0 x$

$36$

$x^{6}$

$x^{5}$

$6 x^{4}$

$x^{5}$

$x^{4}$

$5 x^{4}$

$0 x^{3}$

$5 x^{4}$

$5 x^{3}$

$31 x^{2}$

$5 x^{3}$

$5 x^{2}$

$36 x^{2}$

$0 x$

$36 x^{2}$

$36 x$

$36$

Step 1.5.28

Multiply the new quotient term by the divisor.

$x^{5}$

$x^{4}$

$5 x^{3}$

$5 x^{2}$

$36 x$

$36$

$x$

$1$

$x^{6}$

$0 x^{5}$

$6 x^{4}$

$0 x^{3}$

$31 x^{2}$

$0 x$

$36$

$x^{6}$

$x^{5}$

$6 x^{4}$

$x^{5}$

$x^{4}$

$5 x^{4}$

$0 x^{3}$

$5 x^{4}$

$5 x^{3}$

$31 x^{2}$

$5 x^{3}$

$5 x^{2}$

$36 x^{2}$

$0 x$

$36 x^{2}$

$36 x$

$36$

$36 x$

$36$

Step 1.5.29

The expression needs to be subtracted from the dividend, so change all the signs in $36 x + 36$

$x^{5}$

$x^{4}$

$5 x^{3}$

$5 x^{2}$

$36 x$

$36$

$x$

$1$

$x^{6}$

$0 x^{5}$

$6 x^{4}$

$0 x^{3}$

$31 x^{2}$

$0 x$

$36$

$x^{6}$

$x^{5}$

$6 x^{4}$

$x^{5}$

$x^{4}$

$5 x^{4}$

$0 x^{3}$

$5 x^{4}$

$5 x^{3}$

$31 x^{2}$

$5 x^{3}$

$5 x^{2}$

$36 x^{2}$

$0 x$

$36 x^{2}$

$36 x$

$36$

$36 x$

$36$

Step 1.5.30

After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.

$x^{5}$

$x^{4}$

$5 x^{3}$

$5 x^{2}$

$36 x$

$36$

$x$

$1$

$x^{6}$

$0 x^{5}$

$6 x^{4}$

$0 x^{3}$

$31 x^{2}$

$0 x$

$36$

$x^{6}$

$x^{5}$

$6 x^{4}$

$x^{5}$

$x^{4}$

$5 x^{4}$

$0 x^{3}$

$5 x^{4}$

$5 x^{3}$

$31 x^{2}$

$5 x^{3}$

$5 x^{2}$

$36 x^{2}$

$0 x$

$36 x^{2}$

$36 x$

$36$

$36 x$

$36$

$0$

Step 1.5.31

Since the remander is $0$ , the final answer is the quotient.

$x^{5} - x^{4} - 5 x^{3} + 5 x^{2} - 36 x + 36$

Step 1.6

Write $x^{6} - 6 x^{4} - 31 x^{2} + 36$ as a set of factors.

$f (x) = (x + 1) (x^{5} - x^{4} - 5 x^{3} + 5 x^{2} - 36 x + 36)$

Step 2

Regroup terms.

$f (x) = (x + 1) (x^{5} - 5 x^{3} - 36 x - x^{4} + 5 x^{2} + 36)$

Step 3

Factor $x$ out of $x^{5} - 5 x^{3} - 36 x$ .

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Step 3.1

Factor $x$ out of $x^{5}$ .

$f (x) = (x + 1) (x \cdot x^{4} - 5 x^{3} - 36 x - x^{4} + 5 x^{2} + 36)$

Step 3.2

Factor $x$ out of $- 5 x^{3}$ .

$f (x) = (x + 1) (x \cdot x^{4} + x (- 5 x^{2}) - 36 x - x^{4} + 5 x^{2} + 36)$

Step 3.3

Factor $x$ out of $- 36 x$ .

$f (x) = (x + 1) (x \cdot x^{4} + x (- 5 x^{2}) + x \cdot - 36 - x^{4} + 5 x^{2} + 36)$

Step 3.4

Factor $x$ out of $x \cdot x^{4} + x (- 5 x^{2})$ .

$f (x) = (x + 1) (x (x^{4} - 5 x^{2}) + x \cdot - 36 - x^{4} + 5 x^{2} + 36)$

Step 3.5

Factor $x$ out of $x (x^{4} - 5 x^{2}) + x \cdot - 36$ .

$f (x) = (x + 1) (x (x^{4} - 5 x^{2} - 36) - x^{4} + 5 x^{2} + 36)$

Step 4

Rewrite $x^{4}$ as ${(x^{2})}^{2}$ .

$f (x) = (x + 1) (x ({(x^{2})}^{2} - 5 x^{2} - 36) - x^{4} + 5 x^{2} + 36)$

Step 5

Let $u = x^{2}$ . Substitute $u$ for all occurrences of $x^{2}$ .

$f (x) = (x + 1) (x (u^{2} - 5 u - 36) - x^{4} + 5 x^{2} + 36)$

Step 6

Factor $u^{2} - 5 u - 36$ using the AC method.

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Step 6.1

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 $- 36$ and whose sum is $- 5$ .

$- 9, 4$

Step 6.2

Write the factored form using these integers.

$f (x) = (x + 1) (x ((u - 9) (u + 4)) - x^{4} + 5 x^{2} + 36)$

Step 7

Replace all occurrences of $u$ with $x^{2}$ .

$f (x) = (x + 1) (x ((x^{2} - 9) (x^{2} + 4)) - x^{4} + 5 x^{2} + 36)$

Step 8

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

$f (x) = (x + 1) (x ((x^{2} - 3^{2}) (x^{2} + 4)) - x^{4} + 5 x^{2} + 36)$

Step 9

Factor.

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Step 9.1

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 $b = 3$ .

$f (x) = (x + 1) (x ((x + 3) (x - 3) (x^{2} + 4)) - x^{4} + 5 x^{2} + 36)$

Step 9.2

Remove unnecessary parentheses.

$f (x) = (x + 1) (x (x + 3) (x - 3) (x^{2} + 4) - x^{4} + 5 x^{2} + 36)$

Step 10

Rewrite $x^{4}$ as ${(x^{2})}^{2}$ .

$f (x) = (x + 1) (x (x + 3) (x - 3) (x^{2} + 4) - {(x^{2})}^{2} + 5 x^{2} + 36)$

Step 11

Let $u = x^{2}$ . Substitute $u$ for all occurrences of $x^{2}$ .

$f (x) = (x + 1) (x (x + 3) (x - 3) (x^{2} + 4) - u^{2} + 5 u + 36)$

Step 12

Factor by grouping.

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Step 12.1

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 $a \cdot c = - 1 \cdot 36 = - 36$ and whose sum is $b = 5$ .

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Step 12.1.1

Factor $5$ out of $5 u$ .

$f (x) = (x + 1) (x (x + 3) (x - 3) (x^{2} + 4) - u^{2} + 5 (u) + 36)$

Step 12.1.2

Rewrite $5$ as $- 4$ plus $9$

$f (x) = (x + 1) (x (x + 3) (x - 3) (x^{2} + 4) - u^{2} + (- 4 + 9) u + 36)$

Step 12.1.3

Apply the distributive property.

$f (x) = (x + 1) (x (x + 3) (x - 3) (x^{2} + 4) - u^{2} - 4 u + 9 u + 36)$

Step 12.2

Factor out the greatest common factor from each group.

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Step 12.2.1

Group the first two terms and the last two terms.

$f (x) = (x + 1) (x (x + 3) (x - 3) (x^{2} + 4) - u^{2} - 4 u + 9 u + 36)$

Step 12.2.2

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

$f (x) = (x + 1) (x (x + 3) (x - 3) (x^{2} + 4) + u (- u - 4) - 9 (- u - 4))$

Step 12.3

Factor the polynomial by factoring out the greatest common factor, $- u - 4$ .

$f (x) = (x + 1) (x (x + 3) (x - 3) (x^{2} + 4) + (- u - 4) (u - 9))$

Step 13

Replace all occurrences of $u$ with $x^{2}$ .

$f (x) = (x + 1) (x (x + 3) (x - 3) (x^{2} + 4) + (- x^{2} - 4) (x^{2} - 9))$

Step 14

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

$f (x) = (x + 1) (x (x + 3) (x - 3) (x^{2} + 4) + (- x^{2} - 4) (x^{2} - 3^{2}))$

Step 15

Factor.

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Step 15.1

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 $b = 3$ .

$f (x) = (x + 1) (x (x + 3) (x - 3) (x^{2} + 4) + (- x^{2} - 4) ((x + 3) (x - 3)))$

Step 15.2

Remove unnecessary parentheses.

$f (x) = (x + 1) (x (x + 3) (x - 3) (x^{2} + 4) + (- x^{2} - 4) (x + 3) (x - 3))$

Step 16

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

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Step 16.1

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

$f (x) = (x + 1) ((x + 3) (x - 3) ((x) (x^{2} + 4)) + (- x^{2} - 4) (x + 3) (x - 3))$

Step 16.2

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

$f (x) = (x + 1) ((x + 3) (x - 3) ((x) (x^{2} + 4)) + (x + 3) (x - 3) (- x^{2} - 4))$

Step 16.3

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

$f (x) = (x + 1) ((x + 3) (x - 3) ((x) (x^{2} + 4) - x^{2} - 4))$

Step 17

Apply the distributive property.

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

Step 18

Multiply $x$ by $x^{2}$ by adding the exponents.

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Step 18.1

Multiply $x$ by $x^{2}$ .

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Step 18.1.1

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

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

Step 18.1.2

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

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

Step 18.2

Add $1$ and $2$ .

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

Step 19

Move $4$ to the left of $x$ .

$f (x) = (x + 1) ((x + 3) (x - 3) (x^{3} + 4 x - x^{2} - 4))$

Step 20

Reorder terms.

$f (x) = (x + 1) ((x + 3) (x - 3) (x^{3} - x^{2} + 4 x - 4))$

Step 21

Factor.

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Step 21.1

Factor.

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Step 21.1.1

Rewrite $x^{3} - x^{2} + 4 x - 4$ in a factored form.

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Step 21.1.1.1

Factor out the greatest common factor from each group.

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Step 21.1.1.1.1

Group the first two terms and the last two terms.

$f (x) = (x + 1) ((x + 3) (x - 3) ((x^{3} - x^{2}) + 4 x - 4))$

Step 21.1.1.1.2

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

$f (x) = (x + 1) ((x + 3) (x - 3) (x^{2} (x - 1) + 4 (x - 1)))$

Step 21.1.1.2

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

$f (x) = (x + 1) ((x + 3) (x - 3) ((x - 1) (x^{2} + 4)))$

Step 21.1.2

Remove unnecessary parentheses.

$f (x) = (x + 1) ((x + 3) (x - 3) (x - 1) (x^{2} + 4))$

Step 21.2

Remove unnecessary parentheses.

$f (x) = (x + 1) (x + 3) (x - 3) (x - 1) (x^{2} + 4)$