Algebra Examples

$\frac{x^{2} + 3 x - 4}{x^{2} + 4 x + 4} \cdot \frac{2 x^{2} + 4 x}{x^{2} - 4 x + 3}$

Step 1

Factor $x^{2} + 3 x - 4$ using the AC method.

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Step 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 $- 4$ and whose sum is $3$ .

$- 1, 4$

Step 1.2

Write the factored form using these integers.

$\frac{(x - 1) (x + 4)}{x^{2} + 4 x + 4} \cdot \frac{2 x^{2} + 4 x}{x^{2} - 4 x + 3}$

Step 2

Factor using the perfect square rule.

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Step 2.1

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

$\frac{(x - 1) (x + 4)}{x^{2} + 4 x + 2^{2}} \cdot \frac{2 x^{2} + 4 x}{x^{2} - 4 x + 3}$

Step 2.2

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

$4 x = 2 \cdot x \cdot 2$

Step 2.3

Rewrite the polynomial.

$\frac{(x - 1) (x + 4)}{x^{2} + 2 \cdot x \cdot 2 + 2^{2}} \cdot \frac{2 x^{2} + 4 x}{x^{2} - 4 x + 3}$

Step 2.4

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

$\frac{(x - 1) (x + 4)}{{(x + 2)}^{2}} \cdot \frac{2 x^{2} + 4 x}{x^{2} - 4 x + 3}$

Step 3

Factor $2 x$ out of $2 x^{2} + 4 x$ .

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Step 3.1

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

$\frac{(x - 1) (x + 4)}{{(x + 2)}^{2}} \cdot \frac{2 x (x) + 4 x}{x^{2} - 4 x + 3}$

Step 3.2

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

$\frac{(x - 1) (x + 4)}{{(x + 2)}^{2}} \cdot \frac{2 x (x) + 2 x (2)}{x^{2} - 4 x + 3}$

Step 3.3

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

$\frac{(x - 1) (x + 4)}{{(x + 2)}^{2}} \cdot \frac{2 x (x + 2)}{x^{2} - 4 x + 3}$

Step 4

Factor $x^{2} - 4 x + 3$ using the AC method.

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Step 4.1

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 $3$ and whose sum is $- 4$ .

$- 3, - 1$

Step 4.2

Write the factored form using these integers.

$\frac{(x - 1) (x + 4)}{{(x + 2)}^{2}} \cdot \frac{2 x (x + 2)}{(x - 3) (x - 1)}$

Step 5

Simplify terms.

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Step 5.1

Combine.

$\frac{(x - 1) (x + 4) (2 x (x + 2))}{{(x + 2)}^{2} ((x - 3) (x - 1))}$

Step 5.2

Cancel the common factor of $x - 1$ .

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Step 5.2.1

Cancel the common factor.

$\frac{(x - 1) (x + 4) (2 x (x + 2))}{{(x + 2)}^{2} ((x - 3) (x - 1))}$

Step 5.2.2

Rewrite the expression.

$\frac{(x + 4) (2 x (x + 2))}{{(x + 2)}^{2} (x - 3)}$

Step 5.3

Cancel the common factor of $x + 2$ and ${(x + 2)}^{2}$ .

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Step 5.3.1

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

$\frac{(x + 2) ((x + 4) (2 x))}{{(x + 2)}^{2} (x - 3)}$

Step 5.3.2

Cancel the common factors.

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Step 5.3.2.1

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

$\frac{(x + 2) ((x + 4) (2 x))}{(x + 2) ((x + 2) (x - 3))}$

Step 5.3.2.2

Cancel the common factor.

$\frac{(x + 2) ((x + 4) (2 x))}{(x + 2) ((x + 2) (x - 3))}$

Step 5.3.2.3

Rewrite the expression.

$\frac{(x + 4) (2 x)}{(x + 2) (x - 3)}$

Step 5.4

Simplify the expression.

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Step 5.4.1

Move $2$ to the left of $x + 4$ .

$\frac{2 \cdot (x + 4) x}{(x + 2) (x - 3)}$

Step 5.4.2

Reorder factors in $\frac{2 (x + 4) x}{(x + 2) (x - 3)}$ .

$\frac{2 x (x + 4)}{(x + 2) (x - 3)}$