Part 1:

Question

A rectangular garden has a walk around it of a width x. The garden is 20 ft by 15 ft. Write a function representing the combined area, A(x), of the garden walk. Write as a polynomial in standard form.

Part 2:
Use the function you came up with in the previous part to find the combined area if the walkway is 3ft.

Answer 1

Area of garden itself = 20(15) ft^2 = 300 ft^2
Area of walk and garden = (20+2x)(15+2x) ft^2

area of walk alone = A(x) = (20+2x)(15+2x) - 300 ft^2

Now plug in x = 3 and evaluate