Algebra Examples

$2 x^{4} - 5 x^{3} - 20 x^{2} + 115 x - 52$

Step 1

Regroup terms.

$- 5 x^{3} - 20 x^{2} + 2 x^{4} + 115 x - 52$

Step 2

Factor $- 5 x^{2}$ out of $- 5 x^{3} - 20 x^{2}$ .

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Factor $- 5 x^{2}$ out of $- 5 x^{3}$ .

$- 5 x^{2} (x) - 20 x^{2} + 2 x^{4} + 115 x - 52$

Factor $- 5 x^{2}$ out of $- 20 x^{2}$ .

$- 5 x^{2} (x) - 5 x^{2} (4) + 2 x^{4} + 115 x - 52$

Factor $- 5 x^{2}$ out of $- 5 x^{2} (x) - 5 x^{2} (4)$ .

$- 5 x^{2} (x + 4) + 2 x^{4} + 115 x - 52$

Step 3

Factor $2 x^{4} + 115 x - 52$ using the rational roots test.

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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.

$p = \pm 1, \pm 52, \pm 2, \pm 26, \pm 4, \pm 13 q = \pm 1, \pm 2$

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

$\pm 1, \pm 0.5, \pm 52, \pm 26, \pm 2, \pm 13, \pm 4, \pm 6.5$

Substitute $- 4$ and simplify the expression. In this case, the expression is equal to $0$ so $- 4$ is a root of the polynomial.

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Substitute $- 4$ into the polynomial.

$2 {(- 4)}^{4} + 115 \cdot - 4 - 52$

Raise $- 4$ to the power of $4$ .

$2 \cdot 256 + 115 \cdot - 4 - 52$

Multiply $2$ by $256$ .

$512 + 115 \cdot - 4 - 52$

Multiply $115$ by $- 4$ .

$512 - 460 - 52$

Subtract $460$ from $512$ .

$52 - 52$

Subtract $52$ from $52$ .

$0$

Since $- 4$ is a known root, divide the polynomial by $x + 4$ to find the quotient polynomial. This polynomial can then be used to find the remaining roots.

$\frac{2 x^{4} + 115 x - 52}{x + 4}$

Divide $2 x^{4} + 115 x - 52$ by $x + 4$ .

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

$x$

$4$

$2 x^{4}$

$0 x^{3}$

$0 x^{2}$

$115 x$

$52$

Divide the highest order term in the dividend $2 x^{4}$ by the highest order term in divisor $x$ .

$2 x^{3}$

$x$

$4$

$2 x^{4}$

$0 x^{3}$

$0 x^{2}$

$115 x$

$52$

Multiply the new quotient term by the divisor.

$2 x^{3}$

$x$

$4$

$2 x^{4}$

$0 x^{3}$

$0 x^{2}$

$115 x$

$52$

$2 x^{4}$

$8 x^{3}$

The expression needs to be subtracted from the dividend, so change all the signs in $2 x^{4} + 8 x^{3}$

$2 x^{3}$

$x$

$4$

$2 x^{4}$

$0 x^{3}$

$0 x^{2}$

$115 x$

$52$

$2 x^{4}$

$8 x^{3}$

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

$2 x^{3}$

$x$

$4$

$2 x^{4}$

$0 x^{3}$

$0 x^{2}$

$115 x$

$52$

$2 x^{4}$

$8 x^{3}$

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

$2 x^{3}$

$x$

$4$

$2 x^{4}$

$0 x^{3}$

$0 x^{2}$

$115 x$

$52$

$2 x^{4}$

$8 x^{3}$

$0 x^{2}$

Divide the highest order term in the dividend $- 8 x^{3}$ by the highest order term in divisor $x$ .

$2 x^{3}$

$8 x^{2}$

$x$

$4$

$2 x^{4}$

$0 x^{3}$

$0 x^{2}$

$115 x$

$52$

$2 x^{4}$

$8 x^{3}$

$0 x^{2}$

Multiply the new quotient term by the divisor.

$2 x^{3}$

$8 x^{2}$

$x$

$4$

$2 x^{4}$

$0 x^{3}$

$0 x^{2}$

$115 x$

$52$

$2 x^{4}$

$8 x^{3}$

$0 x^{2}$

$8 x^{3}$

$32 x^{2}$

The expression needs to be subtracted from the dividend, so change all the signs in $- 8 x^{3} - 32 x^{2}$

$2 x^{3}$

$8 x^{2}$

$x$

$4$

$2 x^{4}$

$0 x^{3}$

$0 x^{2}$

$115 x$

$52$

$2 x^{4}$

$8 x^{3}$

$0 x^{2}$

$8 x^{3}$

$32 x^{2}$

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

$2 x^{3}$

$8 x^{2}$

$x$

$4$

$2 x^{4}$

$0 x^{3}$

$0 x^{2}$

$115 x$

$52$

$2 x^{4}$

$8 x^{3}$

$0 x^{2}$

$8 x^{3}$

$32 x^{2}$

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

$2 x^{3}$

$8 x^{2}$

$x$

$4$

$2 x^{4}$

$0 x^{3}$

$0 x^{2}$

$115 x$

$52$

$2 x^{4}$

$8 x^{3}$

$0 x^{2}$

$8 x^{3}$

$32 x^{2}$

$115 x$

Divide the highest order term in the dividend $32 x^{2}$ by the highest order term in divisor $x$ .

$2 x^{3}$

$8 x^{2}$

$32 x$

$x$

$4$

$2 x^{4}$

$0 x^{3}$

$0 x^{2}$

$115 x$

$52$

$2 x^{4}$

$8 x^{3}$

$0 x^{2}$

$8 x^{3}$

$32 x^{2}$

$115 x$

Multiply the new quotient term by the divisor.

$2 x^{3}$

$8 x^{2}$

$32 x$

$x$

$4$

$2 x^{4}$

$0 x^{3}$

$0 x^{2}$

$115 x$

$52$

$2 x^{4}$

$8 x^{3}$

$0 x^{2}$

$8 x^{3}$

$32 x^{2}$

$115 x$

$32 x^{2}$

$128 x$

The expression needs to be subtracted from the dividend, so change all the signs in $32 x^{2} + 128 x$

$2 x^{3}$

$8 x^{2}$

$32 x$

$x$

$4$

$2 x^{4}$

$0 x^{3}$

$0 x^{2}$

$115 x$

$52$

$2 x^{4}$

$8 x^{3}$

$0 x^{2}$

$8 x^{3}$

$32 x^{2}$

$115 x$

$32 x^{2}$

$128 x$

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

$2 x^{3}$

$8 x^{2}$

$32 x$

$x$

$4$

$2 x^{4}$

$0 x^{3}$

$0 x^{2}$

$115 x$

$52$

$2 x^{4}$

$8 x^{3}$

$0 x^{2}$

$8 x^{3}$

$32 x^{2}$

$115 x$

$32 x^{2}$

$128 x$

$13 x$

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

$2 x^{3}$

$8 x^{2}$

$32 x$

$x$

$4$

$2 x^{4}$

$0 x^{3}$

$0 x^{2}$

$115 x$

$52$

$2 x^{4}$

$8 x^{3}$

$0 x^{2}$

$8 x^{3}$

$32 x^{2}$

$115 x$

$32 x^{2}$

$128 x$

$13 x$

$52$

Divide the highest order term in the dividend $- 13 x$ by the highest order term in divisor $x$ .

$2 x^{3}$

$8 x^{2}$

$32 x$

$13$

$x$

$4$

$2 x^{4}$

$0 x^{3}$

$0 x^{2}$

$115 x$

$52$

$2 x^{4}$

$8 x^{3}$

$0 x^{2}$

$8 x^{3}$

$32 x^{2}$

$115 x$

$32 x^{2}$

$128 x$

$13 x$

$52$

Multiply the new quotient term by the divisor.

$2 x^{3}$

$8 x^{2}$

$32 x$

$13$

$x$

$4$

$2 x^{4}$

$0 x^{3}$

$0 x^{2}$

$115 x$

$52$

$2 x^{4}$

$8 x^{3}$

$0 x^{2}$

$8 x^{3}$

$32 x^{2}$

$115 x$

$32 x^{2}$

$128 x$

$13 x$

$52$

$13 x$

$52$

The expression needs to be subtracted from the dividend, so change all the signs in $- 13 x - 52$

$2 x^{3}$

$8 x^{2}$

$32 x$

$13$

$x$

$4$

$2 x^{4}$

$0 x^{3}$

$0 x^{2}$

$115 x$

$52$

$2 x^{4}$

$8 x^{3}$

$0 x^{2}$

$8 x^{3}$

$32 x^{2}$

$115 x$

$32 x^{2}$

$128 x$

$13 x$

$52$

$13 x$

$52$

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

$2 x^{3}$

$8 x^{2}$

$32 x$

$13$

$x$

$4$

$2 x^{4}$

$0 x^{3}$

$0 x^{2}$

$115 x$

$52$

$2 x^{4}$

$8 x^{3}$

$0 x^{2}$

$8 x^{3}$

$32 x^{2}$

$115 x$

$32 x^{2}$

$128 x$

$13 x$

$52$

$13 x$

$52$

$0$

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

$2 x^{3} - 8 x^{2} + 32 x - 13$

Write $2 x^{4} + 115 x - 52$ as a set of factors.

$- 5 x^{2} (x + 4) + (x + 4) (2 x^{3} - 8 x^{2} + 32 x - 13)$

Step 4

Factor $x + 4$ out of $- 5 x^{2} (x + 4) + (x + 4) (2 x^{3} - 8 x^{2} + 32 x - 13)$ .

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Factor $x + 4$ out of $- 5 x^{2} (x + 4)$ .

$(x + 4) (- 5 x^{2}) + (x + 4) (2 x^{3} - 8 x^{2} + 32 x - 13)$

Factor $x + 4$ out of $(x + 4) (- 5 x^{2}) + (x + 4) (2 x^{3} - 8 x^{2} + 32 x - 13)$ .

$(x + 4) (- 5 x^{2} + 2 x^{3} - 8 x^{2} + 32 x - 13)$

Step 5

Subtract $8 x^{2}$ from $- 5 x^{2}$ .

$(x + 4) (2 x^{3} - 13 x^{2} + 32 x - 13)$

Step 6

Factor.

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Factor $2 x^{3} - 13 x^{2} + 32 x - 13$ using the rational roots test.

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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.

$p = \pm 1, \pm 13 q = \pm 1, \pm 2$

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

$\pm 1, \pm 0.5, \pm 13, \pm 6.5$

Substitute $0.5$ and simplify the expression. In this case, the expression is equal to $0$ so $0.5$ is a root of the polynomial.

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Substitute $0.5$ into the polynomial.

$2 \cdot {0.5}^{3} - 13 \cdot {0.5}^{2} + 32 \cdot 0.5 - 13$

Raise $0.5$ to the power of $3$ .

$2 \cdot 0.125 - 13 \cdot {0.5}^{2} + 32 \cdot 0.5 - 13$

Multiply $2$ by $0.125$ .

$0.25 - 13 \cdot {0.5}^{2} + 32 \cdot 0.5 - 13$

Raise $0.5$ to the power of $2$ .

$0.25 - 13 \cdot 0.25 + 32 \cdot 0.5 - 13$

Multiply $- 13$ by $0.25$ .

$0.25 - 3.25 + 32 \cdot 0.5 - 13$

Subtract $3.25$ from $0.25$ .

$- 3 + 32 \cdot 0.5 - 13$

Multiply $32$ by $0.5$ .

$- 3 + 16 - 13$

Add $- 3$ and $16$ .

$13 - 13$

Subtract $13$ from $13$ .

$0$

Since $0.5$ is a known root, divide the polynomial by $2 x - 1$ to find the quotient polynomial. This polynomial can then be used to find the remaining roots.

$\frac{2 x^{3} - 13 x^{2} + 32 x - 13}{2 x - 1}$

Divide $2 x^{3} - 13 x^{2} + 32 x - 13$ by $2 x - 1$ .

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

$2 x$

$1$

$2 x^{3}$

$13 x^{2}$

$32 x$

$13$

Divide the highest order term in the dividend $2 x^{3}$ by the highest order term in divisor $2 x$ .

					$x^{2}$
	$2 x$	-	$1$		$2 x^{3}$	-	$13 x^{2}$	+	$32 x$	-	$13$

Multiply the new quotient term by the divisor.

				$x^{2}$
$2 x$	-	$1$		$2 x^{3}$	-	$13 x^{2}$	+	$32 x$	-	$13$
			+	$2 x^{3}$	-	$x^{2}$

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

				$x^{2}$
$2 x$	-	$1$		$2 x^{3}$	-	$13 x^{2}$	+	$32 x$	-	$13$
			-	$2 x^{3}$	+	$x^{2}$

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

				$x^{2}$
$2 x$	-	$1$		$2 x^{3}$	-	$13 x^{2}$	+	$32 x$	-	$13$
			-	$2 x^{3}$	+	$x^{2}$
					-	$12 x^{2}$

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

				$x^{2}$
$2 x$	-	$1$		$2 x^{3}$	-	$13 x^{2}$	+	$32 x$	-	$13$
			-	$2 x^{3}$	+	$x^{2}$
					-	$12 x^{2}$	+	$32 x$

Divide the highest order term in the dividend $- 12 x^{2}$ by the highest order term in divisor $2 x$ .

				$x^{2}$	-	$6 x$
$2 x$	-	$1$		$2 x^{3}$	-	$13 x^{2}$	+	$32 x$	-	$13$
			-	$2 x^{3}$	+	$x^{2}$
					-	$12 x^{2}$	+	$32 x$

Multiply the new quotient term by the divisor.

				$x^{2}$	-	$6 x$
$2 x$	-	$1$		$2 x^{3}$	-	$13 x^{2}$	+	$32 x$	-	$13$
			-	$2 x^{3}$	+	$x^{2}$
					-	$12 x^{2}$	+	$32 x$
					-	$12 x^{2}$	+	$6 x$

The expression needs to be subtracted from the dividend, so change all the signs in $- 12 x^{2} + 6 x$

				$x^{2}$	-	$6 x$
$2 x$	-	$1$		$2 x^{3}$	-	$13 x^{2}$	+	$32 x$	-	$13$
			-	$2 x^{3}$	+	$x^{2}$
					-	$12 x^{2}$	+	$32 x$
					+	$12 x^{2}$	-	$6 x$

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

				$x^{2}$	-	$6 x$
$2 x$	-	$1$		$2 x^{3}$	-	$13 x^{2}$	+	$32 x$	-	$13$
			-	$2 x^{3}$	+	$x^{2}$
					-	$12 x^{2}$	+	$32 x$
					+	$12 x^{2}$	-	$6 x$
							+	$26 x$

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

				$x^{2}$	-	$6 x$
$2 x$	-	$1$		$2 x^{3}$	-	$13 x^{2}$	+	$32 x$	-	$13$
			-	$2 x^{3}$	+	$x^{2}$
					-	$12 x^{2}$	+	$32 x$
					+	$12 x^{2}$	-	$6 x$
							+	$26 x$	-	$13$

Divide the highest order term in the dividend $26 x$ by the highest order term in divisor $2 x$ .

				$x^{2}$	-	$6 x$	+	$13$
$2 x$	-	$1$		$2 x^{3}$	-	$13 x^{2}$	+	$32 x$	-	$13$
			-	$2 x^{3}$	+	$x^{2}$
					-	$12 x^{2}$	+	$32 x$
					+	$12 x^{2}$	-	$6 x$
							+	$26 x$	-	$13$

Multiply the new quotient term by the divisor.

				$x^{2}$	-	$6 x$	+	$13$
$2 x$	-	$1$		$2 x^{3}$	-	$13 x^{2}$	+	$32 x$	-	$13$
			-	$2 x^{3}$	+	$x^{2}$
					-	$12 x^{2}$	+	$32 x$
					+	$12 x^{2}$	-	$6 x$
							+	$26 x$	-	$13$
							+	$26 x$	-	$13$

The expression needs to be subtracted from the dividend, so change all the signs in $26 x - 13$

				$x^{2}$	-	$6 x$	+	$13$
$2 x$	-	$1$		$2 x^{3}$	-	$13 x^{2}$	+	$32 x$	-	$13$
			-	$2 x^{3}$	+	$x^{2}$
					-	$12 x^{2}$	+	$32 x$
					+	$12 x^{2}$	-	$6 x$
							+	$26 x$	-	$13$
							-	$26 x$	+	$13$

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

				$x^{2}$	-	$6 x$	+	$13$
$2 x$	-	$1$		$2 x^{3}$	-	$13 x^{2}$	+	$32 x$	-	$13$
			-	$2 x^{3}$	+	$x^{2}$
					-	$12 x^{2}$	+	$32 x$
					+	$12 x^{2}$	-	$6 x$
							+	$26 x$	-	$13$
							-	$26 x$	+	$13$
										$0$

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

$x^{2} - 6 x + 13$

Write $2 x^{3} - 13 x^{2} + 32 x - 13$ as a set of factors.

$(x + 4) ((2 x - 1) (x^{2} - 6 x + 13))$

Remove unnecessary parentheses.

$(x + 4) (2 x - 1) (x^{2} - 6 x + 13)$