Algebra Examples

$\frac{a - b}{7 a + 7 b} \div \frac{a^{2} - b^{2}}{a^{2} + 8 a + 16}$

Step 1

To divide by a fraction, multiply by its reciprocal.

$\frac{a - b}{7 a + 7 b} \cdot \frac{a^{2} + 8 a + 16}{a^{2} - b^{2}}$

Step 2

Factor $7$ out of $7 a + 7 b$ .

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Step 2.1

Factor $7$ out of $7 a$ .

$\frac{a - b}{7 (a) + 7 b} \cdot \frac{a^{2} + 8 a + 16}{a^{2} - b^{2}}$

Step 2.2

Factor $7$ out of $7 b$ .

$\frac{a - b}{7 (a) + 7 (b)} \cdot \frac{a^{2} + 8 a + 16}{a^{2} - b^{2}}$

Step 2.3

Factor $7$ out of $7 (a) + 7 (b)$ .

$\frac{a - b}{7 (a + b)} \cdot \frac{a^{2} + 8 a + 16}{a^{2} - b^{2}}$

Step 3

Factor using the perfect square rule.

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Step 3.1

Rewrite $16$ as $4^{2}$ .

$\frac{a - b}{7 (a + b)} \cdot \frac{a^{2} + 8 a + 4^{2}}{a^{2} - b^{2}}$

Step 3.2

Check that the middle term is two times the product of the numbers being squared in the first term and third term.

$8 a = 2 \cdot a \cdot 4$

Step 3.3

Rewrite the polynomial.

$\frac{a - b}{7 (a + b)} \cdot \frac{a^{2} + 2 \cdot a \cdot 4 + 4^{2}}{a^{2} - b^{2}}$

Step 3.4

Factor using the perfect square trinomial rule $a^{2} + 2 a b + b^{2} = {(a + b)}^{2}$ , where $a = a$ and $b = 4$ .

$\frac{a - b}{7 (a + b)} \cdot \frac{{(a + 4)}^{2}}{a^{2} - b^{2}}$

Step 4

Since both terms are perfect squares, factor using the difference of squares formula, $a^{2} - b^{2} = (a + b) (a - b)$ where $a = a$ and $b = b$ .

$\frac{a - b}{7 (a + b)} \cdot \frac{{(a + 4)}^{2}}{(a + b) (a - b)}$

Step 5

Simplify terms.

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Step 5.1

Cancel the common factor of $a - b$ .

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Step 5.1.1

Factor $a - b$ out of $(a + b) (a - b)$ .

$\frac{a - b}{7 (a + b)} \cdot \frac{{(a + 4)}^{2}}{(a - b) (a + b)}$

Step 5.1.2

Cancel the common factor.

$\frac{a - b}{7 (a + b)} \cdot \frac{{(a + 4)}^{2}}{(a - b) (a + b)}$

Step 5.1.3

Rewrite the expression.

$\frac{1}{7 (a + b)} \cdot \frac{{(a + 4)}^{2}}{a + b}$

Step 5.2

Multiply $\frac{1}{7 (a + b)}$ by $\frac{{(a + 4)}^{2}}{a + b}$ .

$\frac{{(a + 4)}^{2}}{7 (a + b) (a + b)}$

Step 6

Raise $a + b$ to the power of $1$ .

$\frac{{(a + 4)}^{2}}{7 ({(a + b)}^{1} (a + b))}$

Step 7

Raise $a + b$ to the power of $1$ .

$\frac{{(a + 4)}^{2}}{7 ({(a + b)}^{1} {(a + b)}^{1})}$

Step 8

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

$\frac{{(a + 4)}^{2}}{7 {(a + b)}^{1 + 1}}$

Step 9

Add $1$ and $1$ .

$\frac{{(a + 4)}^{2}}{7 {(a + b)}^{2}}$