t
4
+
t
2
y
+
y
2
+
t
6
−
y
3
=
=
(
t
2
)
3
+
(
t
2
)
2
+
(
t
2
)
y
+
y
2
−
y
3
=
=
(
t
2
)
3
+
(
t
2
)
2
+
(
t
2
)
y
+
y
2
−
y
3
+
(
t
2
)
2
y
−
(
t
2
)
2
y
+
(
t
2
)
y
2
−
(
t
2
)
y
2
=
=
(
t
2
)
[
(
t
2
)
2
+
(
t
2
)
y
+
y
2
]
−
y
[
(
t
2
)
2
+
(
t
2
)
y
+
y
2
]
+
[
(
t
2
)
2
+
(
t
2
)
y
+
y
2
]
=
=
[
t
2
−
y
+
1
]
[
t
4
+
t
2
y
+
y
2
]
alignc t^4 + t^2 y + y^2 + t^6 - y^3 "=" newline alignc "=" ( t^2 )^3+( t^2 )^2+( t^2 )y+y^2-y^3 "=" newline alignc "=" color red {( t^2 )^3} +( t^2 )^2+( t^2 )y +y^2- color blue {y^3} + color red {(t^2)^2 y} - color blue {(t^2)^2 y} + color red {(t^2)y^2} - color blue {(t^2)y^2} "=" newline "=" color red {( t^2 )} [ color red {( t^2 )^2+(t^2)y+y^2} ] - color blue {y} [ color blue {( t^2)^2 +(t^2) y+ y^2} ] + [( t^2 )^2+(t^2)y+y^2] "=" newline alignc "=" [t^2 -y + 1] [ t^4+t^2 y+y^2]