Answer:
The square has a greater area having an area of 9 cm more than that of the rectangle.
Explanation:
Length of square = x
Length of rectangle = 3+x
Width of rectangle = x-3
Area of square:
=>

=> x × x
=> x²
Area of Rectangle:
=>

=> (3+x)(x-3)
Using FOIL
=> 3x-9+x²-3x
=> x²-9
From the above calculations, we come to know that the square has a greater area having an area of 9 cm more than that of the rectangle.