Given:
Big square: side length = x + 3
Small square: side length = x
Area of a square = a² where a represents the side length.
Area of big square = (x+3)²
A = (x+3)(x+3)
A = x(x+3) + 3(x+3)
A = x² + 3x + 3x + 9
A = x² + 6x + 9
Area of small square = x²
Total Area = Area of Big square + Area of Small square
Total Area = x² + 6x + 9 + x²
Total Area = 2x² + 6x + 9