Basic Math Examples

$\frac{6}{c + 3} + \frac{3}{c^{2} - 3 c + 9} - \frac{162}{c^{3} + 27}$

Step 1

Simplify the denominator.

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Step 1.1

Rewrite $27$ as $3^{3}$ .

$\frac{6}{c + 3} + \frac{3}{c^{2} - 3 c + 9} - \frac{162}{c^{3} + 3^{3}}$

Step 1.2

Since both terms are perfect cubes, factor using the sum of cubes formula, $a^{3} + b^{3} = (a + b) (a^{2} - a b + b^{2})$ where $a = c$ and $b = 3$ .

$\frac{6}{c + 3} + \frac{3}{c^{2} - 3 c + 9} - \frac{162}{(c + 3) (c^{2} - c \cdot 3 + 3^{2})}$

Step 1.3

Simplify.

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Step 1.3.1

Multiply $3$ by $- 1$ .

$\frac{6}{c + 3} + \frac{3}{c^{2} - 3 c + 9} - \frac{162}{(c + 3) (c^{2} - 3 c + 3^{2})}$

Step 1.3.2

Raise $3$ to the power of $2$ .

$\frac{6}{c + 3} + \frac{3}{c^{2} - 3 c + 9} - \frac{162}{(c + 3) (c^{2} - 3 c + 9)}$

Step 2

To write $\frac{6}{c + 3}$ as a fraction with a common denominator, multiply by $\frac{c^{2} - 3 c + 9}{c^{2} - 3 c + 9}$ .

$\frac{6}{c + 3} \cdot \frac{c^{2} - 3 c + 9}{c^{2} - 3 c + 9} + \frac{3}{c^{2} - 3 c + 9} - \frac{162}{(c + 3) (c^{2} - 3 c + 9)}$

Step 3

To write $\frac{3}{c^{2} - 3 c + 9}$ as a fraction with a common denominator, multiply by $\frac{c + 3}{c + 3}$ .

$\frac{6}{c + 3} \cdot \frac{c^{2} - 3 c + 9}{c^{2} - 3 c + 9} + \frac{3}{c^{2} - 3 c + 9} \cdot \frac{c + 3}{c + 3} - \frac{162}{(c + 3) (c^{2} - 3 c + 9)}$

Step 4

Write each expression with a common denominator of $(c + 3) (c^{2} - 3 c + 9)$ , by multiplying each by an appropriate factor of $1$ .

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Step 4.1

Multiply $\frac{6}{c + 3}$ by $\frac{c^{2} - 3 c + 9}{c^{2} - 3 c + 9}$ .

$\frac{6 (c^{2} - 3 c + 9)}{(c + 3) (c^{2} - 3 c + 9)} + \frac{3}{c^{2} - 3 c + 9} \cdot \frac{c + 3}{c + 3} - \frac{162}{(c + 3) (c^{2} - 3 c + 9)}$

Step 4.2

Multiply $\frac{3}{c^{2} - 3 c + 9}$ by $\frac{c + 3}{c + 3}$ .

$\frac{6 (c^{2} - 3 c + 9)}{(c + 3) (c^{2} - 3 c + 9)} + \frac{3 (c + 3)}{(c^{2} - 3 c + 9) (c + 3)} - \frac{162}{(c + 3) (c^{2} - 3 c + 9)}$

Step 4.3

Reorder the factors of $(c^{2} - 3 c + 9) (c + 3)$ .

$\frac{6 (c^{2} - 3 c + 9)}{(c + 3) (c^{2} - 3 c + 9)} + \frac{3 (c + 3)}{(c + 3) (c^{2} - 3 c + 9)} - \frac{162}{(c + 3) (c^{2} - 3 c + 9)}$

Step 5

Combine the numerators over the common denominator.

$\frac{6 (c^{2} - 3 c + 9) + 3 (c + 3)}{(c + 3) (c^{2} - 3 c + 9)} - \frac{162}{(c + 3) (c^{2} - 3 c + 9)}$

Step 6

Combine the numerators over the common denominator.

$\frac{6 (c^{2} - 3 c + 9) + 3 (c + 3) - 162}{(c + 3) (c^{2} - 3 c + 9)}$

Step 7

Simplify the numerator.

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Step 7.1

Simplify each term.

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Step 7.1.1

Apply the distributive property.

$\frac{6 c^{2} + 6 (- 3 c) + 6 \cdot 9 + 3 (c + 3) - 162}{(c + 3) (c^{2} - 3 c + 9)}$

Step 7.1.2

Simplify.

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Step 7.1.2.1

Multiply $- 3$ by $6$ .

$\frac{6 c^{2} - 18 c + 6 \cdot 9 + 3 (c + 3) - 162}{(c + 3) (c^{2} - 3 c + 9)}$

Step 7.1.2.2

Multiply $6$ by $9$ .

$\frac{6 c^{2} - 18 c + 54 + 3 (c + 3) - 162}{(c + 3) (c^{2} - 3 c + 9)}$

Step 7.1.3

Apply the distributive property.

$\frac{6 c^{2} - 18 c + 54 + 3 c + 3 \cdot 3 - 162}{(c + 3) (c^{2} - 3 c + 9)}$

Step 7.1.4

Multiply $3$ by $3$ .

$\frac{6 c^{2} - 18 c + 54 + 3 c + 9 - 162}{(c + 3) (c^{2} - 3 c + 9)}$

Step 7.2

Add $- 18 c$ and $3 c$ .

$\frac{6 c^{2} - 15 c + 54 + 9 - 162}{(c + 3) (c^{2} - 3 c + 9)}$

Step 7.3

Add $54$ and $9$ .

$\frac{6 c^{2} - 15 c + 63 - 162}{(c + 3) (c^{2} - 3 c + 9)}$

Step 7.4

Subtract $162$ from $63$ .

$\frac{6 c^{2} - 15 c - 99}{(c + 3) (c^{2} - 3 c + 9)}$

Step 8

Simplify the numerator.

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Step 8.1

Factor $3$ out of $6 c^{2} - 15 c - 99$ .

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Step 8.1.1

Factor $3$ out of $6 c^{2}$ .

$\frac{3 (2 c^{2}) - 15 c - 99}{(c + 3) (c^{2} - 3 c + 9)}$

Step 8.1.2

Factor $3$ out of $- 15 c$ .

$\frac{3 (2 c^{2}) + 3 (- 5 c) - 99}{(c + 3) (c^{2} - 3 c + 9)}$

Step 8.1.3

Factor $3$ out of $- 99$ .

$\frac{3 (2 c^{2}) + 3 (- 5 c) + 3 (- 33)}{(c + 3) (c^{2} - 3 c + 9)}$

Step 8.1.4

Factor $3$ out of $3 (2 c^{2}) + 3 (- 5 c)$ .

$\frac{3 (2 c^{2} - 5 c) + 3 (- 33)}{(c + 3) (c^{2} - 3 c + 9)}$

Step 8.1.5

Factor $3$ out of $3 (2 c^{2} - 5 c) + 3 (- 33)$ .

$\frac{3 (2 c^{2} - 5 c - 33)}{(c + 3) (c^{2} - 3 c + 9)}$

Step 8.2

Factor by grouping.

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Step 8.2.1

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 $a \cdot c = 2 \cdot - 33 = - 66$ and whose sum is $b = - 5$ .

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Step 8.2.1.1

Factor $- 5$ out of $- 5 c$ .

$\frac{3 (2 c^{2} - 5 (c) - 33)}{(c + 3) (c^{2} - 3 c + 9)}$

Step 8.2.1.2

Rewrite $- 5$ as $6$ plus $- 11$

$\frac{3 (2 c^{2} + (6 - 11) c - 33)}{(c + 3) (c^{2} - 3 c + 9)}$

Step 8.2.1.3

Apply the distributive property.

$\frac{3 (2 c^{2} + 6 c - 11 c - 33)}{(c + 3) (c^{2} - 3 c + 9)}$

Step 8.2.2

Factor out the greatest common factor from each group.

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Step 8.2.2.1

Group the first two terms and the last two terms.

$\frac{3 ((2 c^{2} + 6 c) - 11 c - 33)}{(c + 3) (c^{2} - 3 c + 9)}$

Step 8.2.2.2

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

$\frac{3 (2 c (c + 3) - 11 (c + 3))}{(c + 3) (c^{2} - 3 c + 9)}$

Step 8.2.3

Factor the polynomial by factoring out the greatest common factor, $c + 3$ .

$\frac{3 ((c + 3) (2 c - 11))}{(c + 3) (c^{2} - 3 c + 9)}$

$\frac{3 (c + 3) (2 c - 11)}{(c + 3) (c^{2} - 3 c + 9)}$

Step 9

Cancel the common factor of $c + 3$ .

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Step 9.1

Cancel the common factor.

$\frac{3 (c + 3) (2 c - 11)}{(c + 3) (c^{2} - 3 c + 9)}$

Step 9.2

Rewrite the expression.

$\frac{3 (2 c - 11)}{c^{2} - 3 c + 9}$