Answer:
(b) area = 29 units²
Explanation:
You want the area of the irregular shape shown in the figure.
Area
The area of a rectangular shape is the product of its length and width:
A = LW
The given shape can be considered to be a 6 unit square with some pieces removed. The area of the remaining shape is the area of that square less the areas of the removed pieces.
Upper Left
The piece removed from the upper left corner is a 2-unit square. Its area is ...
A = (2 units)(2 units) = 4 units²
Lower Right
The piece removed from the lower right side is 3 units by 1 unit, so its area is ...
A = (3 units)(1 units) = 3 units²
Overall
The area of the square before those pieces were removed was ...
A = (6 units)(6 units) = 36 units²
Remaining shape
Then the area of the remaining shape after the pieces are removed is ...
Area = 36 units² -4 units² -3 units² = (36 -7) units² = 29 units²
The area of the figure is 29 units².
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Additional comment
Quite often, the area of an irregular shape is more easily found by subtracting missing areas than by dividing up the existing shape into pieces whose area formulas you know.
The second attachment shows division of the area into smaller rectangles. Working clockwise from upper left, their areas are 1×2, 3×4, 3×1, 3×4, for a total of 2+12+3+12 = 29 square units.