Pre-Algebra Examples

$\frac{x (x - 4)}{4} = 9 - x$

Step 1

Multiply both sides by $4$ .

$\frac{x (x - 4)}{4} \cdot 4 = (9 - x) \cdot 4$

Step 2

Simplify.

Tap for more steps...

Step 2.1

Simplify the left side.

Tap for more steps...

Step 2.1.1

Simplify $\frac{x (x - 4)}{4} \cdot 4$ .

Tap for more steps...

Step 2.1.1.1

Cancel the common factor of $4$ .

Tap for more steps...

Step 2.1.1.1.1

Cancel the common factor.

$\frac{x (x - 4)}{4} \cdot 4 = (9 - x) \cdot 4$

Step 2.1.1.1.2

Rewrite the expression.

$x (x - 4) = (9 - x) \cdot 4$

Step 2.1.1.2

Apply the distributive property.

$x \cdot x + x \cdot - 4 = (9 - x) \cdot 4$

Step 2.1.1.3

Simplify the expression.

Tap for more steps...

Step 2.1.1.3.1

Multiply $x$ by $x$ .

$x^{2} + x \cdot - 4 = (9 - x) \cdot 4$

Step 2.1.1.3.2

Move $- 4$ to the left of $x$ .

$x^{2} - 4 x = (9 - x) \cdot 4$

Step 2.2

Simplify the right side.

Tap for more steps...

Step 2.2.1

Simplify $(9 - x) \cdot 4$ .

Tap for more steps...

Step 2.2.1.1

Apply the distributive property.

$x^{2} - 4 x = 9 \cdot 4 - x \cdot 4$

Step 2.2.1.2

Simplify the expression.

Tap for more steps...

Step 2.2.1.2.1

Multiply $9$ by $4$ .

$x^{2} - 4 x = 36 - x \cdot 4$

Step 2.2.1.2.2

Multiply $4$ by $- 1$ .

$x^{2} - 4 x = 36 - 4 x$

Step 2.2.1.2.3

Reorder $36$ and $- 4 x$ .

$x^{2} - 4 x = - 4 x + 36$

Step 3

Solve for $x$ .

Tap for more steps...

Step 3.1

Move all terms containing $x$ to the left side of the equation.

Tap for more steps...

Step 3.1.1

Add $4 x$ to both sides of the equation.

$x^{2} - 4 x + 4 x = 36$

Step 3.1.2

Combine the opposite terms in $x^{2} - 4 x + 4 x$ .

Tap for more steps...

Step 3.1.2.1

Add $- 4 x$ and $4 x$ .

$x^{2} + 0 = 36$

Step 3.1.2.2

Add $x^{2}$ and $0$ .

$x^{2} = 36$

Step 3.2

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

$x = \pm \sqrt{36}$

Step 3.3

Simplify $\pm \sqrt{36}$ .

Tap for more steps...

Step 3.3.1

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

$x = \pm \sqrt{6^{2}}$

Step 3.3.2

Pull terms out from under the radical, assuming positive real numbers.

$x = \pm 6$

Step 3.4

The complete solution is the result of both the positive and negative portions of the solution.

Tap for more steps...

Step 3.4.1

First, use the positive value of the $\pm$ to find the first solution.

$x = 6$

Step 3.4.2

Next, use the negative value of the $\pm$ to find the second solution.

$x = - 6$

Step 3.4.3

The complete solution is the result of both the positive and negative portions of the solution.

$x = 6, - 6$