Pre-Algebra Examples

$(\frac{a^{2}}{2 a - b} + \frac{b^{2}}{b - 2 a}) \div \frac{{(a + b)}^{2}}{2 a^{2} + a b - b^{2}}$

Step 1

To divide by a fraction, multiply by its reciprocal.

$(\frac{a^{2}}{2 a - b} + \frac{b^{2}}{b - 2 a}) \frac{2 a^{2} + a b - b^{2}}{{(a + b)}^{2}}$

Step 2

Simplify the numerator.

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Step 2.1

Factor by grouping.

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Step 2.1.1

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 $a \cdot c = 2 \cdot - 1 = - 2$ and whose sum is $b = 1$ .

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Step 2.1.1.1

Reorder terms.

$(\frac{a^{2}}{2 a - b} + \frac{b^{2}}{b - 2 a}) \frac{2 a^{2} - b^{2} + a b}{{(a + b)}^{2}}$

Step 2.1.1.2

Reorder $- b^{2}$ and $a b$ .

$(\frac{a^{2}}{2 a - b} + \frac{b^{2}}{b - 2 a}) \frac{2 a^{2} + a b - b^{2}}{{(a + b)}^{2}}$

Step 2.1.1.3

Factor $1$ out of $a b$ .

$(\frac{a^{2}}{2 a - b} + \frac{b^{2}}{b - 2 a}) \frac{2 a^{2} + 1 (a b) - b^{2}}{{(a + b)}^{2}}$

Step 2.1.1.4

Rewrite $1$ as $- 1$ plus $2$

$(\frac{a^{2}}{2 a - b} + \frac{b^{2}}{b - 2 a}) \frac{2 a^{2} + (- 1 + 2) (a b) - b^{2}}{{(a + b)}^{2}}$

Step 2.1.1.5

Apply the distributive property.

$(\frac{a^{2}}{2 a - b} + \frac{b^{2}}{b - 2 a}) \frac{2 a^{2} - 1 (a b) + 2 (a b) - b^{2}}{{(a + b)}^{2}}$

Step 2.1.1.6

Move parentheses.

$(\frac{a^{2}}{2 a - b} + \frac{b^{2}}{b - 2 a}) \frac{2 a^{2} - 1 a b + 2 a b - b^{2}}{{(a + b)}^{2}}$

Step 2.1.2

Factor out the greatest common factor from each group.

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Step 2.1.2.1

Group the first two terms and the last two terms.

$(\frac{a^{2}}{2 a - b} + \frac{b^{2}}{b - 2 a}) \frac{(2 a^{2} - 1 a b) + 2 a b - b^{2}}{{(a + b)}^{2}}$

Step 2.1.2.2

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

$(\frac{a^{2}}{2 a - b} + \frac{b^{2}}{b - 2 a}) \frac{a (2 a - 1 b) + b (2 a - b)}{{(a + b)}^{2}}$

Step 2.1.3

Factor the polynomial by factoring out the greatest common factor, $2 a - 1 b$ .

$(\frac{a^{2}}{2 a - b} + \frac{b^{2}}{b - 2 a}) \frac{(2 a - 1 b) (a + b)}{{(a + b)}^{2}}$

Step 2.2

Rewrite $- 1 b$ as $- b$ .

$(\frac{a^{2}}{2 a - b} + \frac{b^{2}}{b - 2 a}) \frac{(2 a - b) (a + b)}{{(a + b)}^{2}}$

Step 3

Factor $- 1$ out of $b$ .

$(\frac{a^{2}}{2 a - b} + \frac{b^{2}}{- 1 (- b) - 2 a}) \frac{(2 a - b) (a + b)}{{(a + b)}^{2}}$

Step 4

Factor $- 1$ out of $- 2 a$ .

$(\frac{a^{2}}{2 a - b} + \frac{b^{2}}{- 1 (- b) - (2 a)}) \frac{(2 a - b) (a + b)}{{(a + b)}^{2}}$

Step 5

Factor $- 1$ out of $- 1 (- b) - (2 a)$ .

$(\frac{a^{2}}{2 a - b} + \frac{b^{2}}{- 1 (- b + 2 a)}) \frac{(2 a - b) (a + b)}{{(a + b)}^{2}}$

Step 6

Move a negative from the denominator of $\frac{b^{2}}{- 1 (- b + 2 a)}$ to the numerator.

$(\frac{a^{2}}{2 a - b} + \frac{- b^{2}}{- b + 2 a}) \frac{(2 a - b) (a + b)}{{(a + b)}^{2}}$

Step 7

Reorder terms.

$(\frac{a^{2}}{2 a - b} + \frac{- b^{2}}{2 a - b}) \frac{(2 a - b) (a + b)}{{(a + b)}^{2}}$

Step 8

Combine the numerators over the common denominator.

$\frac{a^{2} - b^{2}}{2 a - b} \cdot \frac{(2 a - b) (a + b)}{{(a + b)}^{2}}$

Step 9

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

$\frac{(a + b) (a - b)}{2 a - b} \cdot \frac{(2 a - b) (a + b)}{{(a + b)}^{2}}$

Step 10

Cancel the common factor of $a + b$ .

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Step 10.1

Factor $a + b$ out of ${(a + b)}^{2}$ .

$\frac{(a + b) (a - b)}{2 a - b} \cdot \frac{(2 a - b) (a + b)}{(a + b) (a + b)}$

Step 10.2

Cancel the common factor.

$\frac{(a + b) (a - b)}{2 a - b} \cdot \frac{(2 a - b) (a + b)}{(a + b) (a + b)}$

Step 10.3

Rewrite the expression.

$\frac{a - b}{2 a - b} \cdot \frac{(2 a - b) (a + b)}{a + b}$

Step 11

Cancel the common factor of $2 a - b$ .

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Step 11.1

Cancel the common factor.

$\frac{a - b}{2 a - b} \cdot \frac{(2 a - b) (a + b)}{a + b}$

Step 11.2

Rewrite the expression.

$(a - b) \frac{a + b}{a + b}$

Step 12

Cancel the common factor of $a + b$ .

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Step 12.1

Cancel the common factor.

$(a - b) \frac{a + b}{a + b}$

Step 12.2

Rewrite the expression.

$(a - b) \cdot 1$

Step 13

Multiply $a - b$ by $1$ .

$a - b$