A square has a side length of x+3x + 3x+3. What is the area of the square?
x2+9x^2 + 9x2+9
x2+6x+9x^2 + 6x + 9x2+6x+9
x2+3x+9x^2 + 3x + 9x2+3x+9
4x+124x + 124x+12