3 y - 9*y
y^3 - 9*y
/ 2\ y*\-9 + y /
y*(-9 + y^2)
(x + 3)*x*(x - 3)
((x + 3)*x)*(x - 3)
y*(-3 + y)*(3 + y)
y^3 - 9.0*y