Algebra Examples

$3 x^{3} = 108 x$

Step 1

Subtract $108 x$ from both sides of the equation.

$3 x^{3} - 108 x = 0$

Step 2

Factor $3 x$ out of $3 x^{3} - 108 x$ .

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Step 2.1

Factor $3 x$ out of $3 x^{3}$ .

$3 x (x^{2}) - 108 x = 0$

Step 2.2

Factor $3 x$ out of $- 108 x$ .

$3 x (x^{2}) + 3 x (- 36) = 0$

Step 2.3

Factor $3 x$ out of $3 x (x^{2}) + 3 x (- 36)$ .

$3 x (x^{2} - 36) = 0$

Step 3

Rewrite $36$ as $6^{2}$ .

$3 x (x^{2} - 6^{2}) = 0$

Step 4

Factor.

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Step 4.1

Since both terms are perfect squares, factor using the difference of squares formula, $a^{2} - b^{2} = (a + b) (a - b)$ where $a = x$ and $b = 6$ .

$3 x ((x + 6) (x - 6)) = 0$

Step 4.2

Remove unnecessary parentheses.

$3 x (x + 6) (x - 6) = 0$

Step 5

If any individual factor on the left side of the equation is equal to $0$ , the entire expression will be equal to $0$ .

$x = 0$

$x + 6 = 0$

$x - 6 = 0$

Step 6

Set $x$ equal to $0$ .

$x = 0$

Step 7

Set $x + 6$ equal to $0$ and solve for $x$ .

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Step 7.1

Set $x + 6$ equal to $0$ .

$x + 6 = 0$

Step 7.2

Subtract $6$ from both sides of the equation.

$x = - 6$

Step 8

Set $x - 6$ equal to $0$ and solve for $x$ .

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Step 8.1

Set $x - 6$ equal to $0$ .

$x - 6 = 0$

Step 8.2

Add $6$ to both sides of the equation.

$x = 6$

Step 9

The final solution is all the values that make $3 x (x + 6) (x - 6) = 0$ true.

$x = 0, - 6, 6$