Answer:
18 square yards
Explanation:
You want the area of a garden that fills a back yard that is 4 yd by 6 yd except for a patio that is 3 yd by 2 yd.
Yard area
The area of the backyard is ...
A = LW = (6 yd)(4 yd) = 24 yd²
Patio area
The area of the patio is ...
A = LW = (3 yd)(2 yd) = 6 yd²
Garden area
The garden area is the area of the backyard that is not taken up by the patio:
24 yd² -6 yd² = 18 yd²
The garden covers 18 square yards.
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Additional comment
You can compute this many ways. You can divide the garden area into rectangles or trapezoids, or you can recognize that the garden is 3/4 of the area of the back yard.
(You get two trapezoids by cutting the garden along a line between the upper left corner of the yard and the upper left corner of the patio.)