Algebra Examples

$x^{3} - 6$ by $x + 2$

Step 1

Write the problem as a mathematical expression.

$\frac{x^{3} - 6}{x + 2}$

Step 2

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

$x$

$2$

$x^{3}$

$0 x^{2}$

$0 x$

$6$

Step 3

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

					$x^{2}$
	$x$	+	$2$		$x^{3}$	+	$0 x^{2}$	+	$0 x$	-	$6$

Step 4

Multiply the new quotient term by the divisor.

				$x^{2}$
$x$	+	$2$		$x^{3}$	+	$0 x^{2}$	+	$0 x$	-	$6$
			+	$x^{3}$	+	$2 x^{2}$

Step 5

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

				$x^{2}$
$x$	+	$2$		$x^{3}$	+	$0 x^{2}$	+	$0 x$	-	$6$
			-	$x^{3}$	-	$2 x^{2}$

Step 6

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

				$x^{2}$
$x$	+	$2$		$x^{3}$	+	$0 x^{2}$	+	$0 x$	-	$6$
			-	$x^{3}$	-	$2 x^{2}$
					-	$2 x^{2}$

Step 7

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

				$x^{2}$
$x$	+	$2$		$x^{3}$	+	$0 x^{2}$	+	$0 x$	-	$6$
			-	$x^{3}$	-	$2 x^{2}$
					-	$2 x^{2}$	+	$0 x$

Step 8

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

				$x^{2}$	-	$2 x$
$x$	+	$2$		$x^{3}$	+	$0 x^{2}$	+	$0 x$	-	$6$
			-	$x^{3}$	-	$2 x^{2}$
					-	$2 x^{2}$	+	$0 x$

Step 9

Multiply the new quotient term by the divisor.

				$x^{2}$	-	$2 x$
$x$	+	$2$		$x^{3}$	+	$0 x^{2}$	+	$0 x$	-	$6$
			-	$x^{3}$	-	$2 x^{2}$
					-	$2 x^{2}$	+	$0 x$
					-	$2 x^{2}$	-	$4 x$

Step 10

The expression needs to be subtracted from the dividend, so change all the signs in $- 2 x^{2} - 4 x$

				$x^{2}$	-	$2 x$
$x$	+	$2$		$x^{3}$	+	$0 x^{2}$	+	$0 x$	-	$6$
			-	$x^{3}$	-	$2 x^{2}$
					-	$2 x^{2}$	+	$0 x$
					+	$2 x^{2}$	+	$4 x$

Step 11

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

				$x^{2}$	-	$2 x$
$x$	+	$2$		$x^{3}$	+	$0 x^{2}$	+	$0 x$	-	$6$
			-	$x^{3}$	-	$2 x^{2}$
					-	$2 x^{2}$	+	$0 x$
					+	$2 x^{2}$	+	$4 x$
							+	$4 x$

Step 12

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

				$x^{2}$	-	$2 x$
$x$	+	$2$		$x^{3}$	+	$0 x^{2}$	+	$0 x$	-	$6$
			-	$x^{3}$	-	$2 x^{2}$
					-	$2 x^{2}$	+	$0 x$
					+	$2 x^{2}$	+	$4 x$
							+	$4 x$	-	$6$

Step 13

Divide the highest order term in the dividend $4 x$ by the highest order term in divisor $x$ .

				$x^{2}$	-	$2 x$	+	$4$
$x$	+	$2$		$x^{3}$	+	$0 x^{2}$	+	$0 x$	-	$6$
			-	$x^{3}$	-	$2 x^{2}$
					-	$2 x^{2}$	+	$0 x$
					+	$2 x^{2}$	+	$4 x$
							+	$4 x$	-	$6$

Step 14

Multiply the new quotient term by the divisor.

				$x^{2}$	-	$2 x$	+	$4$
$x$	+	$2$		$x^{3}$	+	$0 x^{2}$	+	$0 x$	-	$6$
			-	$x^{3}$	-	$2 x^{2}$
					-	$2 x^{2}$	+	$0 x$
					+	$2 x^{2}$	+	$4 x$
							+	$4 x$	-	$6$
							+	$4 x$	+	$8$

Step 15

The expression needs to be subtracted from the dividend, so change all the signs in $4 x + 8$

				$x^{2}$	-	$2 x$	+	$4$
$x$	+	$2$		$x^{3}$	+	$0 x^{2}$	+	$0 x$	-	$6$
			-	$x^{3}$	-	$2 x^{2}$
					-	$2 x^{2}$	+	$0 x$
					+	$2 x^{2}$	+	$4 x$
							+	$4 x$	-	$6$
							-	$4 x$	-	$8$

Step 16

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

				$x^{2}$	-	$2 x$	+	$4$
$x$	+	$2$		$x^{3}$	+	$0 x^{2}$	+	$0 x$	-	$6$
			-	$x^{3}$	-	$2 x^{2}$
					-	$2 x^{2}$	+	$0 x$
					+	$2 x^{2}$	+	$4 x$
							+	$4 x$	-	$6$
							-	$4 x$	-	$8$
									-	$14$

Step 17

The final answer is the quotient plus the remainder over the divisor.

$x^{2} - 2 x + 4 - \frac{14}{x + 2}$