4 2 y - 7*y + 9
y^4 - 7*y^2 + 9
/ ____\ / ____\ / ____\ / ____\ | 1 \/ 13 | | 1 \/ 13 | | 1 \/ 13 | | 1 \/ 13 | |x + - - ------|*|x + - - + ------|*|x + - - - ------|*|x + - + ------| \ 2 2 / \ 2 2 / \ 2 2 / \ 2 2 /
(((x + 1/2 - sqrt(13)/2)*(x - 1/2 + sqrt(13)/2))*(x - 1/2 - sqrt(13)/2))*(x + 1/2 + sqrt(13)/2)
4 2 9 + y - 7*y
9 + y^4 - 7*y^2
9.0 + y^4 - 7.0*y^2
2 / 2\ 9 + y *\-7 + y /
9 + y^2*(-7 + y^2)
/ 2\ / 2 \ \-3 + y + y /*\-3 + y - y/
(-3 + y + y^2)*(-3 + y^2 - y)