Algebra Examples

$2 - \frac{12}{4 - x} = \frac{2 x + 4}{x^{2} - 16}$

Step 1

Move all terms not containing $x$ to the right side of the equation.

Tap for more steps...

Step 1.1

Subtract $2$ from both sides of the equation.

$- \frac{12}{4 - x} = \frac{2 x + 4}{x^{2} - 16} - 2$

Step 1.2

Simplify each term.

Tap for more steps...

Step 1.2.1

Factor $2$ out of $2 x + 4$ .

Tap for more steps...

Step 1.2.1.1

Factor $2$ out of $2 x$ .

$- \frac{12}{4 - x} = \frac{2 (x) + 4}{x^{2} - 16} - 2$

Step 1.2.1.2

Factor $2$ out of $4$ .

$- \frac{12}{4 - x} = \frac{2 x + 2 \cdot 2}{x^{2} - 16} - 2$

Step 1.2.1.3

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

$- \frac{12}{4 - x} = \frac{2 (x + 2)}{x^{2} - 16} - 2$

Step 1.2.2

Simplify the denominator.

Tap for more steps...

Step 1.2.2.1

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

$- \frac{12}{4 - x} = \frac{2 (x + 2)}{x^{2} - 4^{2}} - 2$

Step 1.2.2.2

Since both terms are perfect squares, factor using the difference of squares formula, $a^{2} - b^{2} = (a + b) (a - b)$ where $a = x$ and $b = 4$ .

$- \frac{12}{4 - x} = \frac{2 (x + 2)}{(x + 4) (x - 4)} - 2$

Step 2

Find the LCD of the terms in the equation.

Tap for more steps...

Step 2.1

Finding the LCD of a list of values is the same as finding the LCM of the denominators of those values.

$4 - x, (x + 4) (x - 4), 1$

Step 2.2

The LCM is the smallest positive number that all of the numbers divide into evenly.

1. List the prime factors of each number.

2. Multiply each factor the greatest number of times it occurs in either number.

Step 2.3

The number $1$ is not a prime number because it only has one positive factor, which is itself.

Not prime

Step 2.4

The LCM of $1, 1, 1$ is the result of multiplying all prime factors the greatest number of times they occur in either number.

$1$

Step 2.5

The factor for $4 - x$ is $4 - x$ itself.

$(4 - x) = 4 - x$

$(4 - x)$ occurs $1$ time.

Step 2.6

The factor for $x + 4$ is $x + 4$ itself.

$(x + 4) = x + 4$

$(x + 4)$ occurs $1$ time.

Step 2.7

The factor for $x - 4$ is $x - 4$ itself.

$(x - 4) = x - 4$

$(x - 4)$ occurs $1$ time.

Step 2.8

The LCM of $4 - x, x + 4, x - 4$ is the result of multiplying all factors the greatest number of times they occur in either term.

$(4 - x) (x + 4) (x - 4)$

Step 3

Multiply each term in $- \frac{12}{4 - x} = \frac{2 (x + 2)}{(x + 4) (x - 4)} - 2$ by $(4 - x) (x + 4) (x - 4)$ to eliminate the fractions.

Tap for more steps...

Step 3.1

Multiply each term in $- \frac{12}{4 - x} = \frac{2 (x + 2)}{(x + 4) (x - 4)} - 2$ by $(4 - x) (x + 4) (x - 4)$ .

$- \frac{12}{4 - x} ((4 - x) (x + 4) (x - 4)) = \frac{2 (x + 2)}{(x + 4) (x - 4)} ((4 - x) (x + 4) (x - 4)) - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.2

Simplify the left side.

Tap for more steps...

Step 3.2.1

Cancel the common factor of $4 - x$ .

Tap for more steps...

Step 3.2.1.1

Move the leading negative in $- \frac{12}{4 - x}$ into the numerator.

$\frac{- 12}{4 - x} ((4 - x) (x + 4) (x - 4)) = \frac{2 (x + 2)}{(x + 4) (x - 4)} ((4 - x) (x + 4) (x - 4)) - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.2.1.2

Factor $4 - x$ out of $(4 - x) (x + 4) (x - 4)$ .

$\frac{- 12}{4 - x} ((4 - x) ((x + 4) (x - 4))) = \frac{2 (x + 2)}{(x + 4) (x - 4)} ((4 - x) (x + 4) (x - 4)) - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.2.1.3

Cancel the common factor.

$\frac{- 12}{4 - x} ((4 - x) ((x + 4) (x - 4))) = \frac{2 (x + 2)}{(x + 4) (x - 4)} ((4 - x) (x + 4) (x - 4)) - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.2.1.4

Rewrite the expression.

$- 12 ((x + 4) (x - 4)) = \frac{2 (x + 2)}{(x + 4) (x - 4)} ((4 - x) (x + 4) (x - 4)) - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.2.2

Expand $(x + 4) (x - 4)$ using the FOIL Method.

Tap for more steps...

Step 3.2.2.1

Apply the distributive property.

$- 12 (x (x - 4) + 4 (x - 4)) = \frac{2 (x + 2)}{(x + 4) (x - 4)} ((4 - x) (x + 4) (x - 4)) - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.2.2.2

Apply the distributive property.

$- 12 (x \cdot x + x \cdot - 4 + 4 (x - 4)) = \frac{2 (x + 2)}{(x + 4) (x - 4)} ((4 - x) (x + 4) (x - 4)) - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.2.2.3

Apply the distributive property.

$- 12 (x \cdot x + x \cdot - 4 + 4 x + 4 \cdot - 4) = \frac{2 (x + 2)}{(x + 4) (x - 4)} ((4 - x) (x + 4) (x - 4)) - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.2.3

Simplify terms.

Tap for more steps...

Step 3.2.3.1

Combine the opposite terms in $x \cdot x + x \cdot - 4 + 4 x + 4 \cdot - 4$ .

Tap for more steps...

Step 3.2.3.1.1

Reorder the factors in the terms $x \cdot - 4$ and $4 x$ .

$- 12 (x \cdot x - 4 x + 4 x + 4 \cdot - 4) = \frac{2 (x + 2)}{(x + 4) (x - 4)} ((4 - x) (x + 4) (x - 4)) - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.2.3.1.2

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

$- 12 (x \cdot x + 0 + 4 \cdot - 4) = \frac{2 (x + 2)}{(x + 4) (x - 4)} ((4 - x) (x + 4) (x - 4)) - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.2.3.1.3

Add $x \cdot x$ and $0$ .

$- 12 (x \cdot x + 4 \cdot - 4) = \frac{2 (x + 2)}{(x + 4) (x - 4)} ((4 - x) (x + 4) (x - 4)) - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.2.3.2

Simplify each term.

Tap for more steps...

Step 3.2.3.2.1

Multiply $x$ by $x$ .

$- 12 (x^{2} + 4 \cdot - 4) = \frac{2 (x + 2)}{(x + 4) (x - 4)} ((4 - x) (x + 4) (x - 4)) - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.2.3.2.2

Multiply $4$ by $- 4$ .

$- 12 (x^{2} - 16) = \frac{2 (x + 2)}{(x + 4) (x - 4)} ((4 - x) (x + 4) (x - 4)) - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.2.3.3

Simplify by multiplying through.

Tap for more steps...

Step 3.2.3.3.1

Apply the distributive property.

$- 12 x^{2} - 12 \cdot - 16 = \frac{2 (x + 2)}{(x + 4) (x - 4)} ((4 - x) (x + 4) (x - 4)) - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.2.3.3.2

Multiply $- 12$ by $- 16$ .

$- 12 x^{2} + 192 = \frac{2 (x + 2)}{(x + 4) (x - 4)} ((4 - x) (x + 4) (x - 4)) - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.3

Simplify the right side.

Tap for more steps...

Step 3.3.1

Simplify each term.

Tap for more steps...

Step 3.3.1.1

Cancel the common factor of $(x + 4) (x - 4)$ .

Tap for more steps...

Step 3.3.1.1.1

Factor $(x + 4) (x - 4)$ out of $(4 - x) (x + 4) (x - 4)$ .

$- 12 x^{2} + 192 = \frac{2 (x + 2)}{(x + 4) (x - 4)} ((x + 4) (x - 4) (4 - x)) - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.3.1.1.2

Cancel the common factor.

$- 12 x^{2} + 192 = \frac{2 (x + 2)}{(x + 4) (x - 4)} ((x + 4) (x - 4) (4 - x)) - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.3.1.1.3

Rewrite the expression.

$- 12 x^{2} + 192 = 2 (x + 2) (4 - x) - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.3.1.2

Apply the distributive property.

$- 12 x^{2} + 192 = (2 x + 2 \cdot 2) (4 - x) - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.3.1.3

Multiply $2$ by $2$ .

$- 12 x^{2} + 192 = (2 x + 4) (4 - x) - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.3.1.4

Expand $(2 x + 4) (4 - x)$ using the FOIL Method.

Tap for more steps...

Step 3.3.1.4.1

Apply the distributive property.

$- 12 x^{2} + 192 = 2 x (4 - x) + 4 (4 - x) - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.3.1.4.2

Apply the distributive property.

$- 12 x^{2} + 192 = 2 x \cdot 4 + 2 x (- x) + 4 (4 - x) - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.3.1.4.3

Apply the distributive property.

$- 12 x^{2} + 192 = 2 x \cdot 4 + 2 x (- x) + 4 \cdot 4 + 4 (- x) - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.3.1.5

Simplify and combine like terms.

Tap for more steps...

Step 3.3.1.5.1

Simplify each term.

Tap for more steps...

Step 3.3.1.5.1.1

Multiply $4$ by $2$ .

$- 12 x^{2} + 192 = 8 x + 2 x (- x) + 4 \cdot 4 + 4 (- x) - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.3.1.5.1.2

Rewrite using the commutative property of multiplication.

$- 12 x^{2} + 192 = 8 x + 2 \cdot - 1 x \cdot x + 4 \cdot 4 + 4 (- x) - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.3.1.5.1.3

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

Tap for more steps...

Step 3.3.1.5.1.3.1

Move $x$ .

$- 12 x^{2} + 192 = 8 x + 2 \cdot - 1 (x \cdot x) + 4 \cdot 4 + 4 (- x) - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.3.1.5.1.3.2

Multiply $x$ by $x$ .

$- 12 x^{2} + 192 = 8 x + 2 \cdot - 1 x^{2} + 4 \cdot 4 + 4 (- x) - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.3.1.5.1.4

Multiply $2$ by $- 1$ .

$- 12 x^{2} + 192 = 8 x - 2 x^{2} + 4 \cdot 4 + 4 (- x) - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.3.1.5.1.5

Multiply $4$ by $4$ .

$- 12 x^{2} + 192 = 8 x - 2 x^{2} + 16 + 4 (- x) - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.3.1.5.1.6

Multiply $- 1$ by $4$ .

$- 12 x^{2} + 192 = 8 x - 2 x^{2} + 16 - 4 x - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.3.1.5.2

Subtract $4 x$ from $8 x$ .

$- 12 x^{2} + 192 = 4 x - 2 x^{2} + 16 - 2 ((4 - x) (x + 4) (x - 4))$

Step 3.3.1.6

Expand $(4 - x) (x + 4)$ using the FOIL Method.

Tap for more steps...

Step 3.3.1.6.1

Apply the distributive property.

$- 12 x^{2} + 192 = 4 x - 2 x^{2} + 16 - 2 ((4 (x + 4) - x (x + 4)) (x - 4))$

Step 3.3.1.6.2

Apply the distributive property.

$- 12 x^{2} + 192 = 4 x - 2 x^{2} + 16 - 2 ((4 x + 4 \cdot 4 - x (x + 4)) (x - 4))$

Step 3.3.1.6.3

Apply the distributive property.

$- 12 x^{2} + 192 = 4 x - 2 x^{2} + 16 - 2 ((4 x + 4 \cdot 4 - x \cdot x - x \cdot 4) (x - 4))$

Step 3.3.1.7

Simplify and combine like terms.

Tap for more steps...

Step 3.3.1.7.1

Simplify each term.

Tap for more steps...

Step 3.3.1.7.1.1

Multiply $4$ by $4$ .

$- 12 x^{2} + 192 = 4 x - 2 x^{2} + 16 - 2 ((4 x + 16 - x \cdot x - x \cdot 4) (x - 4))$

Step 3.3.1.7.1.2

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

Tap for more steps...

Step 3.3.1.7.1.2.1

Move $x$ .

$- 12 x^{2} + 192 = 4 x - 2 x^{2} + 16 - 2 ((4 x + 16 - (x \cdot x) - x \cdot 4) (x - 4))$

Step 3.3.1.7.1.2.2

Multiply $x$ by $x$ .

$- 12 x^{2} + 192 = 4 x - 2 x^{2} + 16 - 2 ((4 x + 16 - x^{2} - x \cdot 4) (x - 4))$

Step 3.3.1.7.1.3

Multiply $4$ by $- 1$ .

$- 12 x^{2} + 192 = 4 x - 2 x^{2} + 16 - 2 ((4 x + 16 - x^{2} - 4 x) (x - 4))$

Step 3.3.1.7.2

Subtract $4 x$ from $4 x$ .

$- 12 x^{2} + 192 = 4 x - 2 x^{2} + 16 - 2 ((16 - x^{2} + 0) (x - 4))$

Step 3.3.1.7.3

Add $16$ and $0$ .

$- 12 x^{2} + 192 = 4 x - 2 x^{2} + 16 - 2 ((- x^{2} + 16) (x - 4))$

Step 3.3.1.8

Expand $(- x^{2} + 16) (x - 4)$ using the FOIL Method.

Tap for more steps...

Step 3.3.1.8.1

Apply the distributive property.

$- 12 x^{2} + 192 = 4 x - 2 x^{2} + 16 - 2 (- x^{2} (x - 4) + 16 (x - 4))$

Step 3.3.1.8.2

Apply the distributive property.

$- 12 x^{2} + 192 = 4 x - 2 x^{2} + 16 - 2 (- x^{2} x - x^{2} \cdot - 4 + 16 (x - 4))$

Step 3.3.1.8.3

Apply the distributive property.

$- 12 x^{2} + 192 = 4 x - 2 x^{2} + 16 - 2 (- x^{2} x - x^{2} \cdot - 4 + 16 x + 16 \cdot - 4)$

Step 3.3.1.9

Simplify each term.

Tap for more steps...

Step 3.3.1.9.1

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

Tap for more steps...

Step 3.3.1.9.1.1

Move $x$ .

$- 12 x^{2} + 192 = 4 x - 2 x^{2} + 16 - 2 (- (x \cdot x^{2}) - x^{2} \cdot - 4 + 16 x + 16 \cdot - 4)$

Step 3.3.1.9.1.2

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

Tap for more steps...

Step 3.3.1.9.1.2.1

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

$- 12 x^{2} + 192 = 4 x - 2 x^{2} + 16 - 2 (- (x^{1} x^{2}) - x^{2} \cdot - 4 + 16 x + 16 \cdot - 4)$

Step 3.3.1.9.1.2.2

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

$- 12 x^{2} + 192 = 4 x - 2 x^{2} + 16 - 2 (- x^{1 + 2} - x^{2} \cdot - 4 + 16 x + 16 \cdot - 4)$

Step 3.3.1.9.1.3

Add $1$ and $2$ .

$- 12 x^{2} + 192 = 4 x - 2 x^{2} + 16 - 2 (- x^{3} - x^{2} \cdot - 4 + 16 x + 16 \cdot - 4)$

Step 3.3.1.9.2

Multiply $- 4$ by $- 1$ .

$- 12 x^{2} + 192 = 4 x - 2 x^{2} + 16 - 2 (- x^{3} + 4 x^{2} + 16 x + 16 \cdot - 4)$

Step 3.3.1.9.3

Multiply $16$ by $- 4$ .

$- 12 x^{2} + 192 = 4 x - 2 x^{2} + 16 - 2 (- x^{3} + 4 x^{2} + 16 x - 64)$

Step 3.3.1.10

Apply the distributive property.

$- 12 x^{2} + 192 = 4 x - 2 x^{2} + 16 - 2 (- x^{3}) - 2 (4 x^{2}) - 2 (16 x) - 2 \cdot - 64$

Step 3.3.1.11

Simplify.

Tap for more steps...

Step 3.3.1.11.1

Multiply $- 1$ by $- 2$ .

$- 12 x^{2} + 192 = 4 x - 2 x^{2} + 16 + 2 x^{3} - 2 (4 x^{2}) - 2 (16 x) - 2 \cdot - 64$

Step 3.3.1.11.2

Multiply $4$ by $- 2$ .

$- 12 x^{2} + 192 = 4 x - 2 x^{2} + 16 + 2 x^{3} - 8 x^{2} - 2 (16 x) - 2 \cdot - 64$

Step 3.3.1.11.3

Multiply $16$ by $- 2$ .

$- 12 x^{2} + 192 = 4 x - 2 x^{2} + 16 + 2 x^{3} - 8 x^{2} - 32 x - 2 \cdot - 64$

Step 3.3.1.11.4

Multiply $- 2$ by $- 64$ .

$- 12 x^{2} + 192 = 4 x - 2 x^{2} + 16 + 2 x^{3} - 8 x^{2} - 32 x + 128$

Step 3.3.2

Simplify by adding terms.

Tap for more steps...

Step 3.3.2.1

Subtract $32 x$ from $4 x$ .

$- 12 x^{2} + 192 = - 2 x^{2} + 16 + 2 x^{3} - 8 x^{2} - 28 x + 128$

Step 3.3.2.2

Subtract $8 x^{2}$ from $- 2 x^{2}$ .

$- 12 x^{2} + 192 = - 10 x^{2} + 16 + 2 x^{3} - 28 x + 128$

Step 3.3.2.3

Add $16$ and $128$ .

$- 12 x^{2} + 192 = - 10 x^{2} + 2 x^{3} - 28 x + 144$

Step 4

Solve the equation.

Tap for more steps...

Step 4.1

Since $x$ is on the right side of the equation, switch the sides so it is on the left side of the equation.

$- 10 x^{2} + 2 x^{3} - 28 x + 144 = - 12 x^{2} + 192$

Step 4.2

Move all terms containing $x$ to the left side of the equation.

Tap for more steps...

Step 4.2.1

Add $12 x^{2}$ to both sides of the equation.

$- 10 x^{2} + 2 x^{3} - 28 x + 144 + 12 x^{2} = 192$

Step 4.2.2

Add $- 10 x^{2}$ and $12 x^{2}$ .

$2 x^{2} + 2 x^{3} - 28 x + 144 = 192$

Step 4.3

Subtract $192$ from both sides of the equation.

$2 x^{2} + 2 x^{3} - 28 x + 144 - 192 = 0$

Step 4.4

Subtract $192$ from $144$ .

$2 x^{2} + 2 x^{3} - 28 x - 48 = 0$

Step 4.5

Factor the left side of the equation.

Tap for more steps...

Step 4.5.1

Factor $2$ out of $2 x^{2} + 2 x^{3} - 28 x - 48$ .

Tap for more steps...

Step 4.5.1.1

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

$2 (x^{2}) + 2 x^{3} - 28 x - 48 = 0$

Step 4.5.1.2

Factor $2$ out of $2 x^{3}$ .

$2 (x^{2}) + 2 (x^{3}) - 28 x - 48 = 0$

Step 4.5.1.3

Factor $2$ out of $- 28 x$ .

$2 (x^{2}) + 2 (x^{3}) + 2 (- 14 x) - 48 = 0$

Step 4.5.1.4

Factor $2$ out of $- 48$ .

$2 (x^{2}) + 2 x^{3} + 2 (- 14 x) + 2 \cdot - 24 = 0$

Step 4.5.1.5

Factor $2$ out of $2 (x^{2}) + 2 x^{3}$ .

$2 (x^{2} + x^{3}) + 2 (- 14 x) + 2 \cdot - 24 = 0$

Step 4.5.1.6

Factor $2$ out of $2 (x^{2} + x^{3}) + 2 (- 14 x)$ .

$2 (x^{2} + x^{3} - 14 x) + 2 \cdot - 24 = 0$

Step 4.5.1.7

Factor $2$ out of $2 (x^{2} + x^{3} - 14 x) + 2 \cdot - 24$ .

$2 (x^{2} + x^{3} - 14 x - 24) = 0$

Step 4.5.2

Reorder terms.

$2 (x^{3} + x^{2} - 14 x - 24) = 0$

Step 4.5.3

Factor.

Tap for more steps...

Step 4.5.3.1

Factor $x^{3} + x^{2} - 14 x - 24$ using the rational roots test.

Tap for more steps...

Step 4.5.3.1.1

If a polynomial function has integer coefficients, then every rational zero will have the form $\frac{p}{q}$ where $p$ is a factor of the constant and $q$ is a factor of the leading coefficient.

$p = \pm 1, \pm 24, \pm 2, \pm 12, \pm 3, \pm 8, \pm 4, \pm 6$

$q = \pm 1$

Step 4.5.3.1.2

Find every combination of $\pm \frac{p}{q}$ . These are the possible roots of the polynomial function.

$\pm 1, \pm 24, \pm 2, \pm 12, \pm 3, \pm 8, \pm 4, \pm 6$

Step 4.5.3.1.3

Substitute $- 2$ and simplify the expression. In this case, the expression is equal to $0$ so $- 2$ is a root of the polynomial.

Tap for more steps...

Step 4.5.3.1.3.1

Substitute $- 2$ into the polynomial.

${(- 2)}^{3} + {(- 2)}^{2} - 14 \cdot - 2 - 24$

Step 4.5.3.1.3.2

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

$- 8 + {(- 2)}^{2} - 14 \cdot - 2 - 24$

Step 4.5.3.1.3.3

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

$- 8 + 4 - 14 \cdot - 2 - 24$

Step 4.5.3.1.3.4

Add $- 8$ and $4$ .

$- 4 - 14 \cdot - 2 - 24$

Step 4.5.3.1.3.5

Multiply $- 14$ by $- 2$ .

$- 4 + 28 - 24$

Step 4.5.3.1.3.6

Add $- 4$ and $28$ .

$24 - 24$

Step 4.5.3.1.3.7

Subtract $24$ from $24$ .

$0$

Step 4.5.3.1.4

Since $- 2$ is a known root, divide the polynomial by $x + 2$ to find the quotient polynomial. This polynomial can then be used to find the remaining roots.

$\frac{x^{3} + x^{2} - 14 x - 24}{x + 2}$

Step 4.5.3.1.5

Divide $x^{3} + x^{2} - 14 x - 24$ by $x + 2$ .

Tap for more steps...

Step 4.5.3.1.5.1

Set up the polynomials to be divided. If there is not a term for every exponent, insert one with a value of $0$ .

$x$

$2$

$x^{3}$

$x^{2}$

$14 x$

$24$

Step 4.5.3.1.5.2

Divide the highest order term in the dividend $x^{3}$ by the highest order term in divisor $x$ .

					$x^{2}$
	$x$	+	$2$		$x^{3}$	+	$x^{2}$	-	$14 x$	-	$24$

Step 4.5.3.1.5.3

Multiply the new quotient term by the divisor.

				$x^{2}$
$x$	+	$2$		$x^{3}$	+	$x^{2}$	-	$14 x$	-	$24$
			+	$x^{3}$	+	$2 x^{2}$

Step 4.5.3.1.5.4

The expression needs to be subtracted from the dividend, so change all the signs in $x^{3} + 2 x^{2}$

				$x^{2}$
$x$	+	$2$		$x^{3}$	+	$x^{2}$	-	$14 x$	-	$24$
			-	$x^{3}$	-	$2 x^{2}$

Step 4.5.3.1.5.5

After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.

				$x^{2}$
$x$	+	$2$		$x^{3}$	+	$x^{2}$	-	$14 x$	-	$24$
			-	$x^{3}$	-	$2 x^{2}$
					-	$x^{2}$

Step 4.5.3.1.5.6

Pull the next terms from the original dividend down into the current dividend.

				$x^{2}$
$x$	+	$2$		$x^{3}$	+	$x^{2}$	-	$14 x$	-	$24$
			-	$x^{3}$	-	$2 x^{2}$
					-	$x^{2}$	-	$14 x$

Step 4.5.3.1.5.7

Divide the highest order term in the dividend $- x^{2}$ by the highest order term in divisor $x$ .

				$x^{2}$	-	$x$
$x$	+	$2$		$x^{3}$	+	$x^{2}$	-	$14 x$	-	$24$
			-	$x^{3}$	-	$2 x^{2}$
					-	$x^{2}$	-	$14 x$

Step 4.5.3.1.5.8

Multiply the new quotient term by the divisor.

				$x^{2}$	-	$x$
$x$	+	$2$		$x^{3}$	+	$x^{2}$	-	$14 x$	-	$24$
			-	$x^{3}$	-	$2 x^{2}$
					-	$x^{2}$	-	$14 x$
					-	$x^{2}$	-	$2 x$

Step 4.5.3.1.5.9

The expression needs to be subtracted from the dividend, so change all the signs in $- x^{2} - 2 x$

				$x^{2}$	-	$x$
$x$	+	$2$		$x^{3}$	+	$x^{2}$	-	$14 x$	-	$24$
			-	$x^{3}$	-	$2 x^{2}$
					-	$x^{2}$	-	$14 x$
					+	$x^{2}$	+	$2 x$

Step 4.5.3.1.5.10

After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.

				$x^{2}$	-	$x$
$x$	+	$2$		$x^{3}$	+	$x^{2}$	-	$14 x$	-	$24$
			-	$x^{3}$	-	$2 x^{2}$
					-	$x^{2}$	-	$14 x$
					+	$x^{2}$	+	$2 x$
							-	$12 x$

Step 4.5.3.1.5.11

Pull the next terms from the original dividend down into the current dividend.

				$x^{2}$	-	$x$
$x$	+	$2$		$x^{3}$	+	$x^{2}$	-	$14 x$	-	$24$
			-	$x^{3}$	-	$2 x^{2}$
					-	$x^{2}$	-	$14 x$
					+	$x^{2}$	+	$2 x$
							-	$12 x$	-	$24$

Step 4.5.3.1.5.12

Divide the highest order term in the dividend $- 12 x$ by the highest order term in divisor $x$ .

				$x^{2}$	-	$x$	-	$12$
$x$	+	$2$		$x^{3}$	+	$x^{2}$	-	$14 x$	-	$24$
			-	$x^{3}$	-	$2 x^{2}$
					-	$x^{2}$	-	$14 x$
					+	$x^{2}$	+	$2 x$
							-	$12 x$	-	$24$

Step 4.5.3.1.5.13

Multiply the new quotient term by the divisor.

				$x^{2}$	-	$x$	-	$12$
$x$	+	$2$		$x^{3}$	+	$x^{2}$	-	$14 x$	-	$24$
			-	$x^{3}$	-	$2 x^{2}$
					-	$x^{2}$	-	$14 x$
					+	$x^{2}$	+	$2 x$
							-	$12 x$	-	$24$
							-	$12 x$	-	$24$

Step 4.5.3.1.5.14

The expression needs to be subtracted from the dividend, so change all the signs in $- 12 x - 24$

				$x^{2}$	-	$x$	-	$12$
$x$	+	$2$		$x^{3}$	+	$x^{2}$	-	$14 x$	-	$24$
			-	$x^{3}$	-	$2 x^{2}$
					-	$x^{2}$	-	$14 x$
					+	$x^{2}$	+	$2 x$
							-	$12 x$	-	$24$
							+	$12 x$	+	$24$

Step 4.5.3.1.5.15

After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.

				$x^{2}$	-	$x$	-	$12$
$x$	+	$2$		$x^{3}$	+	$x^{2}$	-	$14 x$	-	$24$
			-	$x^{3}$	-	$2 x^{2}$
					-	$x^{2}$	-	$14 x$
					+	$x^{2}$	+	$2 x$
							-	$12 x$	-	$24$
							+	$12 x$	+	$24$
										$0$

Step 4.5.3.1.5.16

Since the remander is $0$ , the final answer is the quotient.

$x^{2} - x - 12$

Step 4.5.3.1.6

Write $x^{3} + x^{2} - 14 x - 24$ as a set of factors.

$2 ((x + 2) (x^{2} - x - 12)) = 0$

Step 4.5.3.2

Remove unnecessary parentheses.

$2 (x + 2) (x^{2} - x - 12) = 0$

Step 4.5.4

Factor.

Tap for more steps...

Step 4.5.4.1

Factor $x^{2} - x - 12$ using the AC method.

Tap for more steps...

Step 4.5.4.1.1

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 $- 12$ and whose sum is $- 1$ .

$- 4, 3$

Step 4.5.4.1.2

Write the factored form using these integers.

$2 (x + 2) ((x - 4) (x + 3)) = 0$

Step 4.5.4.2

Remove unnecessary parentheses.

$2 (x + 2) (x - 4) (x + 3) = 0$

Step 4.6

If any individual factor on the left side of the equation is equal to $0$ , the entire expression will be equal to $0$ .

$x + 2 = 0$

$x - 4 = 0$

$x + 3 = 0$

Step 4.7

Set $x + 2$ equal to $0$ and solve for $x$ .

Tap for more steps...

Step 4.7.1

Set $x + 2$ equal to $0$ .

$x + 2 = 0$

Step 4.7.2

Subtract $2$ from both sides of the equation.

$x = - 2$

Step 4.8

Set $x - 4$ equal to $0$ and solve for $x$ .

Tap for more steps...

Step 4.8.1

Set $x - 4$ equal to $0$ .

$x - 4 = 0$

Step 4.8.2

Add $4$ to both sides of the equation.

$x = 4$

Step 4.9

Set $x + 3$ equal to $0$ and solve for $x$ .

Tap for more steps...

Step 4.9.1

Set $x + 3$ equal to $0$ .

$x + 3 = 0$

Step 4.9.2

Subtract $3$ from both sides of the equation.

$x = - 3$

Step 4.10

The final solution is all the values that make $2 (x + 2) (x - 4) (x + 3) = 0$ true.

$x = - 2, 4, - 3$

Step 5

Exclude the solutions that do not make $2 - \frac{12}{4 - x} = \frac{2 x + 4}{x^{2} - 16}$ true.

$x = - 2, - 3$