Answer:
The area is the product of the length and width (6 * 9). It is also the sum of the areas of the rectangles separated by the dotted line (6 * 5 and 6 * 4). So, 6(9) = 6(5) + 6(4).
Explanation:
Parentheses also mean multiplication in math.
6(9) can be written as 6 * 9, 6(5) can be written as 6 * 5, and 6(4) can be written as 6 * 4.
All the explanation is saying is that the length times width equals the area. The length and width is 6 and 9. The area of the full rectangle is also found by finding the areas of the two separated rectangles in the full rectangle. The lengths and widths of the two separated rectangles are 6 and 5, and 6 and 4. Remember, length times width gets you the area. If you find the area of both of the separated rectangles and add them up, you discover that your answer is equivalent to the area of the full rectangle.