Answer:
The Area of Rectangular Garden is 1044  feet²     
Step-by-step explanation:
According to question 
The perimeter of the garden = 82 ft
Let the length be L ft
The width be W ft
Now as per question 
L = 5 + ( 2× W )
∵ Perimeter of Rectangle = 2 × ( Length + Width )
Or , Perimeter of Rectangle = 2 × ( L+ W )
Or, 82 = 2 × ( L+ W )
Or,  82 = 2 × [ 5 + ( 2 ×W ) + W ) ]
Or,  82 = 2 × ( 5 +3W )
Or,  41 = 5 + 3W
Or, 41 - 5 = 3W
So, 3W= 36
∴    W =  = 12 feet
 = 12 feet
I.e Width = 12 feet
And L = 5 + ( 2× W )
Or, Length = 5 + 24 = 29 feet 
Now The Area of Rectangle = Length × width
So, The Area of Rectangle = 29 ft × 36 ft
The Area of Rectangle is 1044 feet²
Hence The Area of Rectangular Garden is 1044  feet²        Answer