Pre-Algebra Examples

$\frac{x^{3}}{4} = 81$

Step 1

Multiply both sides of the equation by $4$ .

$4 \frac{x^{3}}{4} = 4 \cdot 81$

Step 2

Simplify both sides of the equation.

Tap for more steps...

Step 2.1

Simplify the left side.

Tap for more steps...

Step 2.1.1

Cancel the common factor of $4$ .

Tap for more steps...

Step 2.1.1.1

Cancel the common factor.

$4 \frac{x^{3}}{4} = 4 \cdot 81$

Step 2.1.1.2

Rewrite the expression.

$x^{3} = 4 \cdot 81$

Step 2.2

Simplify the right side.

Tap for more steps...

Step 2.2.1

Multiply $4$ by $81$ .

$x^{3} = 324$

Step 3

Take the specified root of both sides of the equation to eliminate the exponent on the left side.

$x = \sqrt[3]{324}$

Step 4

Simplify $\sqrt[3]{324}$ .

Tap for more steps...

Step 4.1

Rewrite $324$ as $3^{3} \cdot 12$ .

Tap for more steps...

Step 4.1.1

Factor $27$ out of $324$ .

$x = \sqrt[3]{27 (12)}$

Step 4.1.2

Rewrite $27$ as $3^{3}$ .

$x = \sqrt[3]{3^{3} \cdot 12}$

Step 4.2

Pull terms out from under the radical.

$x = 3 \sqrt[3]{12}$

Step 5

The result can be shown in multiple forms.

Exact Form:

$x = 3 \sqrt[3]{12}$

Decimal Form:

$x = 6.86828545 \dots$