Pre-Algebra Examples

$\frac{a^{2} + 4 a + 4}{a^{2} + 6 a + 9} \div \frac{a^{2} + 2 a}{a - 3} \div \frac{a^{2} + 5 a + 6}{a - 2}$

Step 1

To divide by a fraction, multiply by its reciprocal.

$\frac{a^{2} + 4 a + 4}{a^{2} + 6 a + 9} \div \frac{a^{2} + 2 a}{a - 3} \cdot \frac{a - 2}{a^{2} + 5 a + 6}$

Step 2

To divide by a fraction, multiply by its reciprocal.

$\frac{a^{2} + 4 a + 4}{a^{2} + 6 a + 9} \cdot \frac{a - 3}{a^{2} + 2 a} \frac{a - 2}{a^{2} + 5 a + 6}$

Step 3

Factor using the perfect square rule.

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Step 3.1

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

$\frac{a^{2} + 4 a + 2^{2}}{a^{2} + 6 a + 9} \cdot \frac{a - 3}{a^{2} + 2 a} \frac{a - 2}{a^{2} + 5 a + 6}$

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.

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

Step 3.3

Rewrite the polynomial.

$\frac{a^{2} + 2 \cdot a \cdot 2 + 2^{2}}{a^{2} + 6 a + 9} \cdot \frac{a - 3}{a^{2} + 2 a} \frac{a - 2}{a^{2} + 5 a + 6}$

Step 3.4

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

$\frac{{(a + 2)}^{2}}{a^{2} + 6 a + 9} \cdot \frac{a - 3}{a^{2} + 2 a} \frac{a - 2}{a^{2} + 5 a + 6}$

Step 4

Factor using the perfect square rule.

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Step 4.1

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

$\frac{{(a + 2)}^{2}}{a^{2} + 6 a + 3^{2}} \cdot \frac{a - 3}{a^{2} + 2 a} \frac{a - 2}{a^{2} + 5 a + 6}$

Step 4.2

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

$6 a = 2 \cdot a \cdot 3$

Step 4.3

Rewrite the polynomial.

$\frac{{(a + 2)}^{2}}{a^{2} + 2 \cdot a \cdot 3 + 3^{2}} \cdot \frac{a - 3}{a^{2} + 2 a} \frac{a - 2}{a^{2} + 5 a + 6}$

Step 4.4

Factor using the perfect square trinomial rule $a^{2} + 2 a b + b^{2} = {(a + b)}^{2}$ , where $a = a$ and $b = 3$ .

$\frac{{(a + 2)}^{2}}{{(a + 3)}^{2}} \cdot \frac{a - 3}{a^{2} + 2 a} \frac{a - 2}{a^{2} + 5 a + 6}$

Step 5

Simplify terms.

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Step 5.1

Factor $a$ out of $a^{2} + 2 a$ .

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Step 5.1.1

Factor $a$ out of $a^{2}$ .

$\frac{{(a + 2)}^{2}}{{(a + 3)}^{2}} \cdot \frac{a - 3}{a \cdot a + 2 a} \frac{a - 2}{a^{2} + 5 a + 6}$

Step 5.1.2

Factor $a$ out of $2 a$ .

$\frac{{(a + 2)}^{2}}{{(a + 3)}^{2}} \cdot \frac{a - 3}{a \cdot a + a \cdot 2} \frac{a - 2}{a^{2} + 5 a + 6}$

Step 5.1.3

Factor $a$ out of $a \cdot a + a \cdot 2$ .

$\frac{{(a + 2)}^{2}}{{(a + 3)}^{2}} \cdot \frac{a - 3}{a (a + 2)} \frac{a - 2}{a^{2} + 5 a + 6}$

Step 5.2

Cancel the common factor of $a + 2$ .

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Step 5.2.1

Factor $a + 2$ out of ${(a + 2)}^{2}$ .

$\frac{(a + 2) (a + 2)}{{(a + 3)}^{2}} \cdot \frac{a - 3}{a (a + 2)} \frac{a - 2}{a^{2} + 5 a + 6}$

Step 5.2.2

Factor $a + 2$ out of $a (a + 2)$ .

$\frac{(a + 2) (a + 2)}{{(a + 3)}^{2}} \cdot \frac{a - 3}{(a + 2) a} \frac{a - 2}{a^{2} + 5 a + 6}$

Step 5.2.3

Cancel the common factor.

$\frac{(a + 2) (a + 2)}{{(a + 3)}^{2}} \cdot \frac{a - 3}{(a + 2) a} \frac{a - 2}{a^{2} + 5 a + 6}$

Step 5.2.4

Rewrite the expression.

$\frac{a + 2}{{(a + 3)}^{2}} \cdot \frac{a - 3}{a} \frac{a - 2}{a^{2} + 5 a + 6}$

Step 5.3

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

$\frac{(a + 2) (a - 3)}{{(a + 3)}^{2} a} \cdot \frac{a - 2}{a^{2} + 5 a + 6}$

Step 6

Factor $a^{2} + 5 a + 6$ 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 $6$ and whose sum is $5$ .

$2, 3$

Step 6.2

Write the factored form using these integers.

$\frac{(a + 2) (a - 3)}{{(a + 3)}^{2} a} \cdot \frac{a - 2}{(a + 2) (a + 3)}$

Step 7

Simplify terms.

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Step 7.1

Cancel the common factor of $a + 2$ .

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Step 7.1.1

Cancel the common factor.

$\frac{(a + 2) (a - 3)}{{(a + 3)}^{2} a} \cdot \frac{a - 2}{(a + 2) (a + 3)}$

Step 7.1.2

Rewrite the expression.

$\frac{a - 3}{{(a + 3)}^{2} a} \cdot \frac{a - 2}{a + 3}$

Step 7.2

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

$\frac{(a - 3) (a - 2)}{{(a + 3)}^{2} a (a + 3)}$

Step 8

Raise $a + 3$ to the power of $1$ .

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

Step 9

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

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

Step 10

Add $2$ and $1$ .

$\frac{(a - 3) (a - 2)}{a {(a + 3)}^{3}}$