4 2 y - 8*y - 9
y^4 - 8*y^2 - 9
4 2 -9 + y - 8*y
-9 + y^4 - 8*y^2
(x + 3)*(x - 3)*(x + I)*(x - I)
(((x + 3)*(x - 3))*(x + i))*(x - i)
2 / 2\ -9 + y *\-8 + y /
-9 + y^2*(-8 + y^2)
/ 2\ \1 + y /*(-3 + y)*(3 + y)
(1 + y^2)*(-3 + y)*(3 + y)
-9.0 + y^4 - 8.0*y^2