Explanation:
To evaluate
f
(
x
+
1
)
substitute
(
x
+
1
)
for each occurrence of
x
in
f
(
x
)
and calculate the result:
f
(
x
)
=
3
−
1
2
x
becomes:
f
(
x
+
1
)
=
3
−
1
2
(
x
+
1
)
f
(
x
+
1
)
=
3
−
1
2
x
−
(
1
2
⋅
1
)
f
(
x
+
1
)
=
3
−
1
2
x
−
1
2
f
(
x
+
1
)
=
3
−
1
2
−
1
2
x
f
(
x
+
1
)
=
(
2
2
⋅
3
)
−
1
2
−
1
2
x
f
(
x
+
1
)
=
6
2
−
1
2
−
1
2
x
f
(
x
+
1
)
=
6
−
1
2
−
1
2
x
f
(
x
+
1
)
=
5
2
−
1
2
x
Or
f
(
x
+
1
)
=
5
−
x
2
