I
n
[
]
:
=
D
S
o
l
v
e
[
2
x
*
y
'
[
x
]
=
=
(
x
+
2
)
y
[
x
]
^
2
-
(
x
+
4
)
,
y
[
x
]
,
x
]
O
u
t
[
]
=
D
S
o
l
v
e
[
2
x
′
y
[
x
]
-
4
-
x
+
(
2
+
x
)
2
y
[
x
]
,
y
[
x
]
,
x
]