Pre-Algebra Examples

 $\begin{array}{r} l = & 9 - 2 x \\ w = & 4 - 2 x \end{array}$

Step 1

The perimeter of a rectangle is equal to the sum of all sides of the rectangle.

$l e n g t h + l e n g t h + w i d t h + w i d t h = 2 \cdot (l e n g t h) + 2 \cdot (w i d t h)$

Step 2

Substitute the values of the length $l = 9 - 2$ and width $w = 4 - 2$ into the formula for the perimeter of a rectangle.

$2 \cdot (9 - 2) + 2 \cdot (4 - 2)$

Step 3

Simplify each term.

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Step 3.1

Subtract $2$ from $9$ .

$2 \cdot 7 + 2 \cdot (4 - 2)$

Step 3.2

Multiply $2$ by $7$ .

$14 + 2 \cdot (4 - 2)$

Step 3.3

Subtract $2$ from $4$ .

$14 + 2 \cdot 2$

Step 3.4

Multiply $2$ by $2$ .

$14 + 4$

Step 4

Add $14$ and $4$ .

$18$ x