Pre-Algebra Examples

$2 x + 21 - x = 9 + 4 x - 6$

Step 1

Subtract $x$ from $2 x$ .

$x + 21 = 9 + 4 x - 6$

Step 2

Subtract $6$ from $9$ .

$x + 21 = 4 x + 3$

Step 3

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

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Step 3.1

Subtract $4 x$ from both sides of the equation.

$x + 21 - 4 x = 3$

Step 3.2

Subtract $4 x$ from $x$ .

$- 3 x + 21 = 3$

Step 4

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

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Step 4.1

Subtract $21$ from both sides of the equation.

$- 3 x = 3 - 21$

Step 4.2

Subtract $21$ from $3$ .

$- 3 x = - 18$

Step 5

Divide each term in $- 3 x = - 18$ by $- 3$ and simplify.

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Step 5.1

Divide each term in $- 3 x = - 18$ by $- 3$ .

$\frac{- 3 x}{- 3} = \frac{- 18}{- 3}$

Step 5.2

Simplify the left side.

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Step 5.2.1

Cancel the common factor of $- 3$ .

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Step 5.2.1.1

Cancel the common factor.

$\frac{- 3 x}{- 3} = \frac{- 18}{- 3}$

Step 5.2.1.2

Divide $x$ by $1$ .

$x = \frac{- 18}{- 3}$

Step 5.3

Simplify the right side.

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Step 5.3.1

Divide $- 18$ by $- 3$ .

$x = 6$