2 x + 6*x + 9
x^2 + 6*x + 9
x + 3
2 9 + x + 6*x
9 + x^2 + 6*x
2 (3 + x)
(3 + x)^2
9 + x*(6 + x)
9.0 + x^2 + 6.0*x