Which expression is equal to x2+6x+9\sqrt{x^2 + 6x + 9}x2+6x+9 for x≥−3x \geq -3x≥−3?
x+3x + 3x+3
x−3x - 3x−3
x2+3\sqrt{x^2} + 3x2+3
(x+3)2(x+3)^2(x+3)2