Dale has a square garden. he adds a 2-foot-wide walkway around his garden. if the total area of the walkway and garden is 196 square feet, find the dimensions of the garden

Let the side of the garden alone (without walkway) be x.  
Then the area of the garden alone is x^2.  
The walkway is made up as follows:

1) four rectangles of width 2 feet and length x, and 
 2) four squares, each of area 2^2 square feet.

The total walkway area is thus x^2 + 4(2^2) + 4(x*2).  

We want to find the dimensions of the garden.  To do this, we need to find the value of x.

Let's sum up the garden dimensions and the walkway dimensions:

x^2 + 4(2^2) + 4(x*2) = 196 sq ft

x^2 + 16 + 8x = 196 sq ft

x^2 + 8x - 180 = 0

(x-10(x+18) = 0

x=10 or x=-18.  We must discard x=-18, since the side length can't be negative.  We are left with x = 10 feet.

The garden dimensions are (10 feet)^2, or 100 square feet.