Algebra Examples

$8 a^{3} + 125$

Step 1

Rewrite $8 a^{3}$ as ${(2 a)}^{3}$ .

${(2 a)}^{3} + 125$

Step 2

Rewrite $125$ as $5^{3}$ .

${(2 a)}^{3} + 5^{3}$

Step 3

Since both terms are perfect cubes, factor using the sum of cubes formula, $a^{3} + b^{3} = (a + b) (a^{2} - a b + b^{2})$ where $a = 2 a$ and $b = 5$ .

$(2 a + 5) ({(2 a)}^{2} - (2 a) \cdot 5 + 5^{2})$

Step 4

Simplify.

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Step 4.1

Apply the product rule to $2 a$ .

$(2 a + 5) (2^{2} a^{2} - (2 a) \cdot 5 + 5^{2})$

Step 4.2

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

$(2 a + 5) (4 a^{2} - (2 a) \cdot 5 + 5^{2})$

Step 4.3

Multiply $2$ by $- 1$ .

$(2 a + 5) (4 a^{2} - 2 a \cdot 5 + 5^{2})$

Step 4.4

Multiply $5$ by $- 2$ .

$(2 a + 5) (4 a^{2} - 10 a + 5^{2})$

Step 4.5

Raise $5$ to the power of $2$ .

$(2 a + 5) (4 a^{2} - 10 a + 25)$