2 x + 8*x + 16
x^2 + 8*x + 16
x + 4
2 16 + x + 8*x
16 + x^2 + 8*x
16 + x*(8 + x)
2 (4 + x)
(4 + x)^2
16.0 + x^2 + 8.0*x