Step 1:
width of the garden: w
length of the garden: 2w+3
Step 2:
width of the entire plot: w+0.5w=1.5w
length of the entire plot: (2w+3) + 0.5w = 2.5w+3
Step 3:
area of the garden: w(2w+3)
area of the entire plot: 1.5w(2.5w+3)
Step 4:
area of the garden: 2w^2+3w
area of the entire plot: 3.75w^2+4.5w
Step 5:
area of border= area of the entire plot - area of the garden
area of border= 3.75w^2+4.5w - (2w^2+3w)
Step 6:
area of border= 3.75w^2+4.5w - 2w^2 - 3w
Step 7:
area of border= 1.75w^2+1.5w