Final answer:
The area of Joe's garden is 8 square feet, and the area of Spencer's garden is 9 square feet.
Step-by-step explanation:
To find the area of Joe's garden, we need to know the length and width. Since both the length and width are even numbers and the perimeter is 12 feet, we can assume that the dimensions are 2 feet by 4 feet (or 4 feet by 2 feet). The area of a rectangle is found by multiplying the length by the width, so the area of Joe's garden is 8 square feet.
For Spencer's garden, since the length and width are odd numbers and the perimeter is 12 feet, let's assume the dimensions are 3 feet by 3 feet. Using the same formula, the area of Spencer's garden is 9 square feet.