30 8 +------------------------------------------------------------+-------------------+ I I I 2 I 2 * 30 I 2 * 8 I I I I +------------------------------------------------------------+-------------------+
The entire large rectangle above is 38 units long and 2 units wide. Its area is length times width, so the area is 2 * 38. 38 is also the same as 30 + 8, so the area can also be written as 2(30 + 8).
The left rectangle is 30 units long and 2 units wide. Its area is 2 * 30. The right rectangle is 2 units long and 8 units wide. Its area is 2 * 8.
If you add the areas of the small rectangles, you get 2 * 30 + 2 * 8
If you add the two small areas, you get the area of the laerge rectangle, so
