Trigonometry Examples

$| 2 x - 1 | = 9$

Step 1

Remove the absolute value term. This creates a $\pm$ on the right side of the equation because $| x | = \pm x$ .

$2 x - 1 = \pm 9$

Step 2

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

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Step 2.1

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

$2 x - 1 = 9$

Step 2.2

Move all terms not containing $x$ to the right side of the equation.

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Step 2.2.1

Add $1$ to both sides of the equation.

$2 x = 9 + 1$

Step 2.2.2

Add $9$ and $1$ .

$2 x = 10$

Step 2.3

Divide each term in $2 x = 10$ by $2$ and simplify.

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Step 2.3.1

Divide each term in $2 x = 10$ by $2$ .

$\frac{2 x}{2} = \frac{10}{2}$

Step 2.3.2

Simplify the left side.

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Step 2.3.2.1

Cancel the common factor of $2$ .

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Step 2.3.2.1.1

Cancel the common factor.

$\frac{2 x}{2} = \frac{10}{2}$

Step 2.3.2.1.2

Divide $x$ by $1$ .

$x = \frac{10}{2}$

Step 2.3.3

Simplify the right side.

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Step 2.3.3.1

Divide $10$ by $2$ .

$x = 5$

Step 2.4

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

$2 x - 1 = - 9$

Step 2.5

Move all terms not containing $x$ to the right side of the equation.

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Step 2.5.1

Add $1$ to both sides of the equation.

$2 x = - 9 + 1$

Step 2.5.2

Add $- 9$ and $1$ .

$2 x = - 8$

Step 2.6

Divide each term in $2 x = - 8$ by $2$ and simplify.

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Step 2.6.1

Divide each term in $2 x = - 8$ by $2$ .

$\frac{2 x}{2} = \frac{- 8}{2}$

Step 2.6.2

Simplify the left side.

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Step 2.6.2.1

Cancel the common factor of $2$ .

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Step 2.6.2.1.1

Cancel the common factor.

$\frac{2 x}{2} = \frac{- 8}{2}$

Step 2.6.2.1.2

Divide $x$ by $1$ .

$x = \frac{- 8}{2}$

Step 2.6.3

Simplify the right side.

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Step 2.6.3.1

Divide $- 8$ by $2$ .

$x = - 4$

Step 2.7

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

$x = 5, - 4$