2 2*x + 7*x + 3
2*x^2 + 7*x + 3
2 3 + 2*x + 7*x
3 + 2*x^2 + 7*x
(x + 3)*(x + 1/2)
(1 + 2*x)*(3 + x)
3.0 + 2.0*x^2 + 7.0*x
3 + x*(7 + 2*x)