Part A:
A local volunteer group plans to build a community garden. The outline below represents the proposed shape of the garden.


Write an expression for the area of this proposed garden. Show the reasoning you used to find the expression.

Part B:
The volunteer group has plans to double the area of the garden in a few years. They have come up with two plans to complete this. The first plan increases the length of the base of the garden by b feet, as shown in the diagram below.


Write an expression in terms of x to represent the value of b. Explain the reasoning you used to find the value of b.

Part C:
The volunteer group's second plan to double the area changes the shape of the garden to a larger rectangle, as shown in the diagram below.


Can the value of y be represented as a polynomial with integer coefficients? Justify your reasoning.