Algebra Examples

$\frac{5 + 7 i}{1 + i}$

Step 1

Multiply the numerator and denominator of $\frac{5 + 7 i}{1 + 1 i}$ by the conjugate of $1 + 1 i$ to make the denominator real.

$\frac{5 + 7 i}{1 + 1 i} \cdot \frac{1 - i}{1 - i}$

Step 2

Multiply.

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Step 2.1

Combine.

$\frac{(5 + 7 i) (1 - i)}{(1 + 1 i) (1 - i)}$

Step 2.2

Simplify the numerator.

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Step 2.2.1

Expand $(5 + 7 i) (1 - i)$ using the FOIL Method.

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Step 2.2.1.1

Apply the distributive property.

$\frac{5 (1 - i) + 7 i (1 - i)}{(1 + 1 i) (1 - i)}$

Step 2.2.1.2

Apply the distributive property.

$\frac{5 \cdot 1 + 5 (- i) + 7 i (1 - i)}{(1 + 1 i) (1 - i)}$

Step 2.2.1.3

Apply the distributive property.

$\frac{5 \cdot 1 + 5 (- i) + 7 i \cdot 1 + 7 i (- i)}{(1 + 1 i) (1 - i)}$

Step 2.2.2

Simplify and combine like terms.

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Step 2.2.2.1

Simplify each term.

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Step 2.2.2.1.1

Multiply $5$ by $1$ .

$\frac{5 + 5 (- i) + 7 i \cdot 1 + 7 i (- i)}{(1 + 1 i) (1 - i)}$

Step 2.2.2.1.2

Multiply $- 1$ by $5$ .

$\frac{5 - 5 i + 7 i \cdot 1 + 7 i (- i)}{(1 + 1 i) (1 - i)}$

Step 2.2.2.1.3

Multiply $7$ by $1$ .

$\frac{5 - 5 i + 7 i + 7 i (- i)}{(1 + 1 i) (1 - i)}$

Step 2.2.2.1.4

Multiply $7 i (- i)$ .

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Step 2.2.2.1.4.1

Multiply $- 1$ by $7$ .

$\frac{5 - 5 i + 7 i - 7 i i}{(1 + 1 i) (1 - i)}$

Step 2.2.2.1.4.2

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

$\frac{5 - 5 i + 7 i - 7 (i^{1} i)}{(1 + 1 i) (1 - i)}$

Step 2.2.2.1.4.3

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

$\frac{5 - 5 i + 7 i - 7 (i^{1} i^{1})}{(1 + 1 i) (1 - i)}$

Step 2.2.2.1.4.4

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

$\frac{5 - 5 i + 7 i - 7 i^{1 + 1}}{(1 + 1 i) (1 - i)}$

Step 2.2.2.1.4.5

Add $1$ and $1$ .

$\frac{5 - 5 i + 7 i - 7 i^{2}}{(1 + 1 i) (1 - i)}$

Step 2.2.2.1.5

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

$\frac{5 - 5 i + 7 i - 7 \cdot - 1}{(1 + 1 i) (1 - i)}$

Step 2.2.2.1.6

Multiply $- 7$ by $- 1$ .

$\frac{5 - 5 i + 7 i + 7}{(1 + 1 i) (1 - i)}$

Step 2.2.2.2

Add $5$ and $7$ .

$\frac{12 - 5 i + 7 i}{(1 + 1 i) (1 - i)}$

Step 2.2.2.3

Add $- 5 i$ and $7 i$ .

$\frac{12 + 2 i}{(1 + 1 i) (1 - i)}$

Step 2.3

Simplify the denominator.

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Step 2.3.1

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

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Step 2.3.1.1

Apply the distributive property.

$\frac{12 + 2 i}{1 (1 - i) + 1 i (1 - i)}$

Step 2.3.1.2

Apply the distributive property.

$\frac{12 + 2 i}{1 \cdot 1 + 1 (- i) + 1 i (1 - i)}$

Step 2.3.1.3

Apply the distributive property.

$\frac{12 + 2 i}{1 \cdot 1 + 1 (- i) + 1 i \cdot 1 + 1 i (- i)}$

Step 2.3.2

Simplify.

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Step 2.3.2.1

Multiply $1$ by $1$ .

$\frac{12 + 2 i}{1 + 1 (- i) + 1 i \cdot 1 + 1 i (- i)}$

Step 2.3.2.2

Multiply $- 1$ by $1$ .

$\frac{12 + 2 i}{1 - 1 i + 1 i \cdot 1 + 1 i (- i)}$

Step 2.3.2.3

Multiply $1$ by $1$ .

$\frac{12 + 2 i}{1 - 1 i + 1 i + 1 i (- i)}$

Step 2.3.2.4

Multiply $- 1$ by $1$ .

$\frac{12 + 2 i}{1 - 1 i + 1 i - i i}$

Step 2.3.2.5

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

$\frac{12 + 2 i}{1 - 1 i + 1 i - (i^{1} i)}$

Step 2.3.2.6

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

$\frac{12 + 2 i}{1 - 1 i + 1 i - (i^{1} i^{1})}$

Step 2.3.2.7

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

$\frac{12 + 2 i}{1 - 1 i + 1 i - i^{1 + 1}}$

Step 2.3.2.8

Add $1$ and $1$ .

$\frac{12 + 2 i}{1 - 1 i + 1 i - i^{2}}$

Step 2.3.2.9

Add $- 1 i$ and $1 i$ .

$\frac{12 + 2 i}{1 + 0 - i^{2}}$

Step 2.3.2.10

Add $1$ and $0$ .

$\frac{12 + 2 i}{1 - i^{2}}$

Step 2.3.3

Simplify each term.

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Step 2.3.3.1

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

$\frac{12 + 2 i}{1 - - 1}$

Step 2.3.3.2

Multiply $- 1$ by $- 1$ .

$\frac{12 + 2 i}{1 + 1}$

Step 2.3.4

Add $1$ and $1$ .

$\frac{12 + 2 i}{2}$

Step 3

Cancel the common factor of $12 + 2 i$ and $2$ .

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Step 3.1

Factor $2$ out of $12$ .

$\frac{2 \cdot 6 + 2 i}{2}$

Step 3.2

Factor $2$ out of $2 i$ .

$\frac{2 \cdot 6 + 2 (i)}{2}$

Step 3.3

Factor $2$ out of $2 (6) + 2 (i)$ .

$\frac{2 (6 + i)}{2}$

Step 3.4

Cancel the common factors.

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Step 3.4.1

Factor $2$ out of $2$ .

$\frac{2 (6 + i)}{2 (1)}$

Step 3.4.2

Cancel the common factor.

$\frac{2 (6 + i)}{2 \cdot 1}$

Step 3.4.3

Rewrite the expression.

$\frac{6 + i}{1}$

Step 3.4.4

Divide $6 + i$ by $1$ .

$6 + i$