Final answer:
Marshall could use the expression 2(w+l) to calculate the perimeter of his rectangular garden, as it correctly accounts for the sum of all the sides of the rectangle.
Step-by-step explanation:
Marshall has a rectangular garden that he wants to enclose with a fence and he used the expression 2w+2l to calculate the perimeter, where w represents the width and l represents the length of the garden. To find another expression for calculating the perimeter of the rectangular garden, which is the sum of all sides, we would take option D) 2(w+l), as it simplifies the total length of the two widths and the two lengths of the garden.
The other options presented do not correctly calculate the perimeter of a rectangle:
A) wl represents the area of the rectangle, not the perimeter.
B) 2wl would give a value that is twice the area, which is not related to the perimeter.
C) 2(w+2l) would incorrectly double the length's value before adding it to the width's value, providing an inaccurate perimeter.