1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Evgesh-ka [11]
3 years ago
9

Find the sum of the first 18 terms of the arithmetic sequence whose nth term is an = 3n - 1.

Mathematics
1 answer:
vodka [1.7K]3 years ago
7 0

Answer:

495

Step-by-step explanation:

In order to find the sum of the first 18 terms you have to find the 18th term and the first term using the equation given.

a1=3(1)-1        a1=2

a18=3(18)-1   a18= 53

Then plug in 53 for an, 18 for n, and 2 in for a1 in the sum equation: Sn=n/2(a1+an)  

Sn=18/2(2+53)  Solve for sn= 495

You might be interested in
Help with my math please
Sindrei [870]

Answer:

j mmmmmmm

Step-by-step explanation:

mmmmmmmmm

6 0
2 years ago
Triangle ABC is similar to triangle DEF.
Sav [38]

Answer: x=7.7, y=40

3/x = 15/38.5

38.5*3=115.5

115.5/15= 7.7

x=7.7


3/8 = 15/y

15*8=120

120/3= 40

y=40


orrrr you can just easily find the scale factor which is 5, multiply 8 by 5 and get 40. And 38.5/5 which is 7.7

7 0
2 years ago
Please help me with the attached math question
levacccp [35]
C.........................

5 0
3 years ago
Find the area of the rhombus pls?
zhannawk [14.2K]

Answer:

imagine doing homework

5 0
3 years ago
Read 2 more answers
A publishing company is going to have 24,000 books printed. There are between 3 and 4 out of every 3,000 printed that will have
ivann1987 [24]
24000(total books) / 3000(batch of books with amount of errors known) = 8

8*3 = 24,
8*4 = 32

There will be between 24 and 32 printing errors.
5 0
3 years ago
Read 2 more answers
Other questions:
  • List the next 3 pattern
    12·2 answers
  • An electrician needs to run a cable from the top of a 40​-foot tower to a transmitter box located 30 feet away from the base of
    14·1 answer
  • Please Help the First Answer Will Get Brainliest!!!!!!!!
    8·1 answer
  • In rectangle ANGEL, AN=16 and AG= 34. Find the perimeter of ANGL
    15·2 answers
  • What are the exact lengths of BC and CF?
    12·2 answers
  • Solve: 3a^2-4b a= -6 b= -5 If you could also leave an explanation that would be great! Thank you for your time!
    10·1 answer
  • Several students were asked how many blocks they walk from home to school each day. The results are shown in the line plot. How
    15·1 answer
  • A geometric sequence has an initial value of 2 and a common ratio of 3. Which formula would be more practical to use if you were
    12·1 answer
  • The question is in the picture below^^<br> Will give brainliest no links
    13·2 answers
  • Does anyone know the answer to this? i’ll mark brainliest
    15·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!