Answer:
nth term = 1 1/2n -1
Step-by-step explanation:
The arithmetic sequence formula is:
a
n
=
a
1
+
(
n
–
1
)
d
Where:
a
n
is the nth term in the sequence
a
1
is the first term in the sequence
n
is the term you are solving for
d
is the common difference for any pair of consecutive numbers in the sequence.
First Term or
n
=
1
:
This is given in the problem.
a
1 = 9
Second Term or
n
=
2
:
Substitute
2 for n
in the formula and substitute the values from the problem giving:
a
2
=
9
+
(
(
2
–
1
)
×
-2
)
a
2
=
9
+
(
1
×
-2
)
a
2
=
9
+-2
a
2
=
7
Fifth Term or n
=
5
:
Substitute in the formula and substitute the values from the problem giving:
a
5
=
9+
(
(
5–
1
)
×
-2
)
a
5
=
9
+
(
4
×
-2
)
a
2
=
9
+
-8
a
2
= 1
Using this same process you should be able to determiner the
Third Term or n
=
3
: and Fourth Term or n
=
4
:
