Each side of the hot tub measures 6 feet.

Please help with question below-

A square hot tub will be placed in the center of an enclosed area near the pool. Each side of the hot tub measures 6 feet. It will be surrounded by x feet of deck on each side. The enclosed space is also square and has an area of 169 square feet. Find the width of the deck space around the hot tub, x.

A. Please help with what is the equation for the area of the enclosed space in the form y = (side length)2. Don't forget to add x to each side of the hot tub. 

B. Substitute the area of the enclosed space for y in your equation. 

C. Solve the equation from Part b for x. 

D. What is the width of the deck around the hot tub? One of the answers from Part c is not reasonable.