Finite Math Examples

$(x + 4) (x - 7 - 2 i) (x - 7 + 2 i)$

Step 1

Expand $(x + 4) (x - 7 - 2 i)$ by multiplying each term in the first expression by each term in the second expression.

$(x \cdot x + x \cdot - 7 + x (- 2 i) + 4 x + 4 \cdot - 7 + 4 (- 2 i)) (x - 7 + 2 i)$

Step 2

Simplify terms.

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Step 2.1

Simplify each term.

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Step 2.1.1

Multiply $x$ by $x$ .

$(x^{2} + x \cdot - 7 + x (- 2 i) + 4 x + 4 \cdot - 7 + 4 (- 2 i)) (x - 7 + 2 i)$

Step 2.1.2

Move $- 7$ to the left of $x$ .

$(x^{2} - 7 \cdot x + x (- 2 i) + 4 x + 4 \cdot - 7 + 4 (- 2 i)) (x - 7 + 2 i)$

Step 2.1.3

Multiply $4$ by $- 7$ .

$(x^{2} - 7 x + x (- 2 i) + 4 x - 28 + 4 (- 2 i)) (x - 7 + 2 i)$

Step 2.1.4

Multiply $- 2$ by $4$ .

$(x^{2} - 7 x + x (- 2 i) + 4 x - 28 - 8 i) (x - 7 + 2 i)$

Step 2.2

Add $- 7 x$ and $4 x$ .

$(x^{2} + x (- 2 i) - 3 x - 28 - 8 i) (x - 7 + 2 i)$

Step 3

Expand $(x^{2} + x (- 2 i) - 3 x - 28 - 8 i) (x - 7 + 2 i)$ by multiplying each term in the first expression by each term in the second expression.

$x^{2} x + x^{2} \cdot - 7 + x^{2} (2 i) + x (- 2 i) x + x (- 2 i) \cdot - 7 + x (- 2 i) (2 i) - 3 x \cdot x - 3 x \cdot - 7 - 3 x (2 i) - 28 x - 28 \cdot - 7 - 28 (2 i) - 8 i x - 8 i \cdot - 7 - 8 i (2 i)$

Step 4

Simplify terms.

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Step 4.1

Simplify each term.

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Step 4.1.1

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

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Step 4.1.1.1

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

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Step 4.1.1.1.1

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

$x^{2} x^{1} + x^{2} \cdot - 7 + x^{2} (2 i) + x (- 2 i) x + x (- 2 i) \cdot - 7 + x (- 2 i) (2 i) - 3 x \cdot x - 3 x \cdot - 7 - 3 x (2 i) - 28 x - 28 \cdot - 7 - 28 (2 i) - 8 i x - 8 i \cdot - 7 - 8 i (2 i)$

Step 4.1.1.1.2

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

$x^{2 + 1} + x^{2} \cdot - 7 + x^{2} (2 i) + x (- 2 i) x + x (- 2 i) \cdot - 7 + x (- 2 i) (2 i) - 3 x \cdot x - 3 x \cdot - 7 - 3 x (2 i) - 28 x - 28 \cdot - 7 - 28 (2 i) - 8 i x - 8 i \cdot - 7 - 8 i (2 i)$

Step 4.1.1.2

Add $2$ and $1$ .

$x^{3} + x^{2} \cdot - 7 + x^{2} (2 i) + x (- 2 i) x + x (- 2 i) \cdot - 7 + x (- 2 i) (2 i) - 3 x \cdot x - 3 x \cdot - 7 - 3 x (2 i) - 28 x - 28 \cdot - 7 - 28 (2 i) - 8 i x - 8 i \cdot - 7 - 8 i (2 i)$

Step 4.1.2

Move $- 7$ to the left of $x^{2}$ .

$x^{3} - 7 \cdot x^{2} + x^{2} (2 i) + x (- 2 i) x + x (- 2 i) \cdot - 7 + x (- 2 i) (2 i) - 3 x \cdot x - 3 x \cdot - 7 - 3 x (2 i) - 28 x - 28 \cdot - 7 - 28 (2 i) - 8 i x - 8 i \cdot - 7 - 8 i (2 i)$

Step 4.1.3

Move $2$ to the left of $x^{2}$ .

$x^{3} - 7 x^{2} + 2 \cdot x^{2} i + x (- 2 i) x + x (- 2 i) \cdot - 7 + x (- 2 i) (2 i) - 3 x \cdot x - 3 x \cdot - 7 - 3 x (2 i) - 28 x - 28 \cdot - 7 - 28 (2 i) - 8 i x - 8 i \cdot - 7 - 8 i (2 i)$

Step 4.1.4

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

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Step 4.1.4.1

Move $x$ .

$x^{3} - 7 x^{2} + 2 x^{2} i + x \cdot x (- 2 i) + x (- 2 i) \cdot - 7 + x (- 2 i) (2 i) - 3 x \cdot x - 3 x \cdot - 7 - 3 x (2 i) - 28 x - 28 \cdot - 7 - 28 (2 i) - 8 i x - 8 i \cdot - 7 - 8 i (2 i)$

Step 4.1.4.2

Multiply $x$ by $x$ .

$x^{3} - 7 x^{2} + 2 x^{2} i + x^{2} (- 2 i) + x (- 2 i) \cdot - 7 + x (- 2 i) (2 i) - 3 x \cdot x - 3 x \cdot - 7 - 3 x (2 i) - 28 x - 28 \cdot - 7 - 28 (2 i) - 8 i x - 8 i \cdot - 7 - 8 i (2 i)$

Step 4.1.5

Multiply $- 7$ by $- 2$ .

$x^{3} - 7 x^{2} + 2 x^{2} i + x^{2} (- 2 i) + x (14 i) + x (- 2 i) (2 i) - 3 x \cdot x - 3 x \cdot - 7 - 3 x (2 i) - 28 x - 28 \cdot - 7 - 28 (2 i) - 8 i x - 8 i \cdot - 7 - 8 i (2 i)$

Step 4.1.6

Move $14$ to the left of $x$ .

$x^{3} - 7 x^{2} + 2 x^{2} i + x^{2} (- 2 i) + 14 \cdot x i + x (- 2 i) (2 i) - 3 x \cdot x - 3 x \cdot - 7 - 3 x (2 i) - 28 x - 28 \cdot - 7 - 28 (2 i) - 8 i x - 8 i \cdot - 7 - 8 i (2 i)$

Step 4.1.7

Multiply $x (- 2 i) (2 i)$ .

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Step 4.1.7.1

Multiply $2$ by $- 2$ .

$x^{3} - 7 x^{2} + 2 x^{2} i + x^{2} (- 2 i) + 14 x i + x (- 4 i) i - 3 x \cdot x - 3 x \cdot - 7 - 3 x (2 i) - 28 x - 28 \cdot - 7 - 28 (2 i) - 8 i x - 8 i \cdot - 7 - 8 i (2 i)$

Step 4.1.7.2

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

$x^{3} - 7 x^{2} + 2 x^{2} i + x^{2} (- 2 i) + 14 x i + x (- 4 (i^{1} i)) - 3 x \cdot x - 3 x \cdot - 7 - 3 x (2 i) - 28 x - 28 \cdot - 7 - 28 (2 i) - 8 i x - 8 i \cdot - 7 - 8 i (2 i)$

Step 4.1.7.3

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

$x^{3} - 7 x^{2} + 2 x^{2} i + x^{2} (- 2 i) + 14 x i + x (- 4 (i^{1} i^{1})) - 3 x \cdot x - 3 x \cdot - 7 - 3 x (2 i) - 28 x - 28 \cdot - 7 - 28 (2 i) - 8 i x - 8 i \cdot - 7 - 8 i (2 i)$

Step 4.1.7.4

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

$x^{3} - 7 x^{2} + 2 x^{2} i + x^{2} (- 2 i) + 14 x i + x (- 4 i^{1 + 1}) - 3 x \cdot x - 3 x \cdot - 7 - 3 x (2 i) - 28 x - 28 \cdot - 7 - 28 (2 i) - 8 i x - 8 i \cdot - 7 - 8 i (2 i)$

Step 4.1.7.5

Add $1$ and $1$ .

$x^{3} - 7 x^{2} + 2 x^{2} i + x^{2} (- 2 i) + 14 x i + x (- 4 i^{2}) - 3 x \cdot x - 3 x \cdot - 7 - 3 x (2 i) - 28 x - 28 \cdot - 7 - 28 (2 i) - 8 i x - 8 i \cdot - 7 - 8 i (2 i)$

Step 4.1.8

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

$x^{3} - 7 x^{2} + 2 x^{2} i + x^{2} (- 2 i) + 14 x i + x (- 4 \cdot - 1) - 3 x \cdot x - 3 x \cdot - 7 - 3 x (2 i) - 28 x - 28 \cdot - 7 - 28 (2 i) - 8 i x - 8 i \cdot - 7 - 8 i (2 i)$

Step 4.1.9

Multiply $- 4$ by $- 1$ .

$x^{3} - 7 x^{2} + 2 x^{2} i + x^{2} (- 2 i) + 14 x i + x \cdot 4 - 3 x \cdot x - 3 x \cdot - 7 - 3 x (2 i) - 28 x - 28 \cdot - 7 - 28 (2 i) - 8 i x - 8 i \cdot - 7 - 8 i (2 i)$

Step 4.1.10

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

$x^{3} - 7 x^{2} + 2 x^{2} i + x^{2} (- 2 i) + 14 x i + 4 \cdot x - 3 x \cdot x - 3 x \cdot - 7 - 3 x (2 i) - 28 x - 28 \cdot - 7 - 28 (2 i) - 8 i x - 8 i \cdot - 7 - 8 i (2 i)$

Step 4.1.11

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

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Step 4.1.11.1

Move $x$ .

$x^{3} - 7 x^{2} + 2 x^{2} i + x^{2} (- 2 i) + 14 x i + 4 x - 3 (x \cdot x) - 3 x \cdot - 7 - 3 x (2 i) - 28 x - 28 \cdot - 7 - 28 (2 i) - 8 i x - 8 i \cdot - 7 - 8 i (2 i)$

Step 4.1.11.2

Multiply $x$ by $x$ .

$x^{3} - 7 x^{2} + 2 x^{2} i + x^{2} (- 2 i) + 14 x i + 4 x - 3 x^{2} - 3 x \cdot - 7 - 3 x (2 i) - 28 x - 28 \cdot - 7 - 28 (2 i) - 8 i x - 8 i \cdot - 7 - 8 i (2 i)$

Step 4.1.12

Multiply $- 7$ by $- 3$ .

$x^{3} - 7 x^{2} + 2 x^{2} i + x^{2} (- 2 i) + 14 x i + 4 x - 3 x^{2} + 21 x - 3 x (2 i) - 28 x - 28 \cdot - 7 - 28 (2 i) - 8 i x - 8 i \cdot - 7 - 8 i (2 i)$

Step 4.1.13

Multiply $2$ by $- 3$ .

$x^{3} - 7 x^{2} + 2 x^{2} i + x^{2} (- 2 i) + 14 x i + 4 x - 3 x^{2} + 21 x - 6 x i - 28 x - 28 \cdot - 7 - 28 (2 i) - 8 i x - 8 i \cdot - 7 - 8 i (2 i)$

Step 4.1.14

Multiply $- 28$ by $- 7$ .

$x^{3} - 7 x^{2} + 2 x^{2} i + x^{2} (- 2 i) + 14 x i + 4 x - 3 x^{2} + 21 x - 6 x i - 28 x + 196 - 28 (2 i) - 8 i x - 8 i \cdot - 7 - 8 i (2 i)$

Step 4.1.15

Multiply $2$ by $- 28$ .

$x^{3} - 7 x^{2} + 2 x^{2} i + x^{2} (- 2 i) + 14 x i + 4 x - 3 x^{2} + 21 x - 6 x i - 28 x + 196 - 56 i - 8 i x - 8 i \cdot - 7 - 8 i (2 i)$

Step 4.1.16

Multiply $- 7$ by $- 8$ .

$x^{3} - 7 x^{2} + 2 x^{2} i + x^{2} (- 2 i) + 14 x i + 4 x - 3 x^{2} + 21 x - 6 x i - 28 x + 196 - 56 i - 8 i x + 56 i - 8 i (2 i)$

Step 4.1.17

Multiply $- 8 i (2 i)$ .

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Step 4.1.17.1

Multiply $2$ by $- 8$ .

$x^{3} - 7 x^{2} + 2 x^{2} i + x^{2} (- 2 i) + 14 x i + 4 x - 3 x^{2} + 21 x - 6 x i - 28 x + 196 - 56 i - 8 i x + 56 i - 16 i i$

Step 4.1.17.2

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

$x^{3} - 7 x^{2} + 2 x^{2} i + x^{2} (- 2 i) + 14 x i + 4 x - 3 x^{2} + 21 x - 6 x i - 28 x + 196 - 56 i - 8 i x + 56 i - 16 (i^{1} i)$

Step 4.1.17.3

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

$x^{3} - 7 x^{2} + 2 x^{2} i + x^{2} (- 2 i) + 14 x i + 4 x - 3 x^{2} + 21 x - 6 x i - 28 x + 196 - 56 i - 8 i x + 56 i - 16 (i^{1} i^{1})$

Step 4.1.17.4

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

$x^{3} - 7 x^{2} + 2 x^{2} i + x^{2} (- 2 i) + 14 x i + 4 x - 3 x^{2} + 21 x - 6 x i - 28 x + 196 - 56 i - 8 i x + 56 i - 16 i^{1 + 1}$

Step 4.1.17.5

Add $1$ and $1$ .

$x^{3} - 7 x^{2} + 2 x^{2} i + x^{2} (- 2 i) + 14 x i + 4 x - 3 x^{2} + 21 x - 6 x i - 28 x + 196 - 56 i - 8 i x + 56 i - 16 i^{2}$

Step 4.1.18

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

$x^{3} - 7 x^{2} + 2 x^{2} i + x^{2} (- 2 i) + 14 x i + 4 x - 3 x^{2} + 21 x - 6 x i - 28 x + 196 - 56 i - 8 i x + 56 i - 16 \cdot - 1$

Step 4.1.19

Multiply $- 16$ by $- 1$ .

$x^{3} - 7 x^{2} + 2 x^{2} i + x^{2} (- 2 i) + 14 x i + 4 x - 3 x^{2} + 21 x - 6 x i - 28 x + 196 - 56 i - 8 i x + 56 i + 16$

Step 4.2

Simplify by adding terms.

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Step 4.2.1

Combine the opposite terms in $x^{3} - 7 x^{2} + 2 x^{2} i + x^{2} (- 2 i) + 14 x i + 4 x - 3 x^{2} + 21 x - 6 x i - 28 x + 196 - 56 i - 8 i x + 56 i + 16$ .

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Step 4.2.1.1

Reorder the factors in the terms $2 x^{2} i$ and $x^{2} (- 2 i)$ .

$x^{3} - 7 x^{2} + 2 i x^{2} - 2 i x^{2} + 14 x i + 4 x - 3 x^{2} + 21 x - 6 x i - 28 x + 196 - 56 i - 8 i x + 56 i + 16$

Step 4.2.1.2

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

$x^{3} - 7 x^{2} + 0 + 14 x i + 4 x - 3 x^{2} + 21 x - 6 x i - 28 x + 196 - 56 i - 8 i x + 56 i + 16$

Step 4.2.1.3

Add $x^{3} - 7 x^{2}$ and $0$ .

$x^{3} - 7 x^{2} + 14 x i + 4 x - 3 x^{2} + 21 x - 6 x i - 28 x + 196 - 56 i - 8 i x + 56 i + 16$

Step 4.2.1.4

Add $- 56 i$ and $56 i$ .

$x^{3} - 7 x^{2} + 14 x i + 4 x - 3 x^{2} + 21 x - 6 x i - 28 x + 196 - 8 i x + 0 + 16$

Step 4.2.1.5

Add $x^{3} - 7 x^{2} + 14 x i + 4 x - 3 x^{2} + 21 x - 6 x i - 28 x + 196 - 8 i x$ and $0$ .

$x^{3} - 7 x^{2} + 14 x i + 4 x - 3 x^{2} + 21 x - 6 x i - 28 x + 196 - 8 i x + 16$

Step 4.2.2

Subtract $3 x^{2}$ from $- 7 x^{2}$ .

$x^{3} - 10 x^{2} + 14 x i + 4 x + 21 x - 6 x i - 28 x + 196 - 8 i x + 16$

Step 4.2.3

Subtract $6 x i$ from $14 x i$ .

$x^{3} - 10 x^{2} + 8 x i + 4 x + 21 x - 28 x + 196 - 8 i x + 16$

Step 4.2.4

Combine the opposite terms in $x^{3} - 10 x^{2} + 8 x i + 4 x + 21 x - 28 x + 196 - 8 i x + 16$ .

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Step 4.2.4.1

Reorder the factors in the terms $8 x i$ and $- 8 i x$ .

$x^{3} - 10 x^{2} + 8 i x + 4 x + 21 x - 28 x + 196 - 8 i x + 16$

Step 4.2.4.2

Subtract $8 i x$ from $8 i x$ .

$x^{3} - 10 x^{2} + 4 x + 21 x - 28 x + 196 + 0 + 16$

Step 4.2.4.3

Add $x^{3} - 10 x^{2} + 4 x + 21 x - 28 x + 196$ and $0$ .

$x^{3} - 10 x^{2} + 4 x + 21 x - 28 x + 196 + 16$

Step 4.2.5

Add $4 x$ and $21 x$ .

$x^{3} - 10 x^{2} + 25 x - 28 x + 196 + 16$

Step 4.2.6

Subtract $28 x$ from $25 x$ .

$x^{3} - 10 x^{2} - 3 x + 196 + 16$

Step 4.2.7

Add $196$ and $16$ .

$x^{3} - 10 x^{2} - 3 x + 212$