Answer:
a
n
=
−
2
n
+
15
Step-by-step explanation:
This is an arithmetic sequence since there is a common difference between each term. In this case, adding
−
2
to the previous term in the sequence gives the next term. In other words,
a
n
=
a
1
+
d
(
n
−
1
)
.
Arithmetic Sequence:
d
=
−
2
This is the formula of an arithmetic sequence.
a
n
=
a
1
+
d
(
n
−
1
)
Substitute in the values of
a
1
=
13
and
d
=
−
2
.
a
n
=
13
+
(
−
2
)
(
n
−
1
)
Simplify each term.
Tap for more steps...
a
n
=
13
−
2
n
+
2
Add
13
and
2
.
a
n
=
−
2
n
+
15
Answer:
21
Step-by-step explanation:
Let x = the number
12x-12 = 240
12x = 252
x = 21
The rate a computer works is 1/time. Working together, you add the rates.
Let new computer be x, old computer be y.
x = y - 7

Rounded to nearest tenth gives:
x = 23 hours
Answer:
the answer is 50 hope this helps
Step-by-step explanation:
4-5=-1
-1+8=7
7+8x8= ?
15x8=120
120/4=50