I
n
[
]
:
=
$
A
s
s
u
m
p
t
i
o
n
s
=
2
a
+
2
b
0
O
u
t
[
]
=
2
a
+
2
b
0
I
n
[
]
:
=
2
(
a
+
b
)
2
(
a
+
b
)
/
/
E
x
p
a
n
d
/
/
S
i
m
p
l
i
f
y
O
u
t
[
]
=
2
(
a
+
b
)
O
u
t
[
]
=
2
a
b