The swimming pool at Spring Valley High School is a rectangle with a width of `30` meters and a length of `24` meters. The principal wants to add a walkway around the perimeter of the pool is a tiled floor that extends `y` meters from the pool on all sides. Write an expression for the combined area of the walkway and pool as a product of two binomials. Simplify the expression in standard form. Provide the algebraic justification in the space provided below.