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
ratelena [41]
2 years ago
5

Which calculation should be used to calculate s9 for the arithmetic sequence an=3n-1

Mathematics
2 answers:
Ganezh [65]2 years ago
7 0

Answer: Choice A

S9 = (9/2)*(2+26)

===============================================

The formula is

Sn = (n/2)*(a1+an)

where

Sn = sum of the first n terms (nth partial sum)

n = number of terms

a1 = first term

an = nth term

In this case,

n = 9

a1 = 2 (plug in n = 1 into the formula an = 3n-1 and simplify)

an = a9 = 26 (plug n = 9 into the formula an = 3n-1 and simplify)

So,

Sn = (n/2)*(a1+an)

S9 = (9/2)*(2+26)

will help us find the sum of the first 9 terms of this arithmetic sequence

mario62 [17]2 years ago
3 0

Answer:

A. S9 = (9/2)*(2+26)


You might be interested in
An artist makes a scale drawing of a new lion enclosure at the zoo. The scale is 1 in : 25 ft. On the drawing, the length of the
8090 [49]

Answer:

The actual length of the lion enclosure is <u>181.25 feet</u>.

Step-by-step explanation:

Given:

An artist makes a scale drawing of a new lion enclosure at the zoo.

The scale is 1 in : 25 ft.

On the drawing, the length of the enclosure is 7.25 inches.

Now, to find the actual length of the lion enclosure in feet.

Let the actual length of the lion enclosure in feet be x.

<em>As given the  scale is 1 in : 25 ft.</em>

<em>So, 1 in is equivalent to 25 ft.</em>

<em>Thus, 7.25 inches is equivalent to </em>x.<em />

Now, to get the actual length of the lion enclosure by using cross multiplication method:

\frac{1}{25} =\frac{7.25}{x}

<em>By cross multiplying we get:</em>

x=181.25\ feet.

Therefore, the actual length of the lion enclosure is 181.25 feet.

4 0
2 years ago
3x^3-24x^2 factor completley
svetoff [14.1K]
3x^3-24x^2=> this is the expression, find what they have in common: 3 and x^2
3x^2(x-8)=> so we took out 3x^2

I hope this helps you:)!
7 0
3 years ago
Read 2 more answers
Jill has to go to the post office before she drops her 3 children off at the elementary school. She is going straight home after
Fantom [35]

Answer:

D i think

Step-by-step explanation:

7 0
2 years ago
Read 2 more answers
Suppose y varies directly as x, and y =15 when x = 3. Find the constant of variation (k).
vovangra [49]

Answer:

k = 5

Step-by-step explanation:

y = kx

15 = k(3)

k = 15/3

k = 5

8 0
3 years ago
For this problem use 3.14 for , and any non-integer answers should be entered as decimals rounded to the hundredths place. Lanno
arsen [322]

Answer:

Step-by-step explanation:

For this problem use 3.14 for , and any non-integer answers should be entered as decimals rounded to the hundredths place. Lannon is designing a carnival game for a school event. She has a large wooden square and she needs to cut out a circle from the middle. The circumference of the circle that she plans to cut out is 56.52 inches. What is the radius

The formula for circumference of a circle = 2πr

Circumference = 56.52 inches

r = Circumference/2π

r = 56.52/2π

7 0
3 years ago
Other questions:
  • Which relationship describes angles 1 and 2?
    7·1 answer
  • PLZ HELP WILL REWARD BRAINLIEST
    7·1 answer
  • Round each number to the nearest whole number. What is the best estimate for the sum of 317.38 82.21? A. 410 B. 400 C. 399 D. 39
    15·2 answers
  • How well did you remember how to combine polynomials?
    12·2 answers
  • Plz help 10 points, plz only answer if you know the answer for sure this is really important to me
    11·1 answer
  • Help.....I need to ace this.
    9·1 answer
  • (x+y) ²+(x-y)²+(x+y)*(x-y)​
    10·1 answer
  • Solve sqrt of 2x+6-4=0. Show work.
    5·2 answers
  • What is 8 1/3×3 3/5×1 1/3
    15·1 answer
  • Evaluate- x=23, y=7: x-1 divided by y+4
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!