–20, –16, –12, –8, –4, . . . What is the the sum of the first 30 terms of the sequence?

Answers

Answer 1

Answer:

Step-by-step explanation:

This is an arithmetic sequence because each term subtracted by the previous term is a constant called the common difference.

an=a+d(n-1) where a is the initial term and d is the common difference

a=-20 and d=-16+20=4 so

an=-20+4(n-1)

an=4n-24

The sum of an arithmetic sequence is the average of the first and last terms times the number of terms

sn=(a1+an)(n/2)

s30=(-20+4(30)-24)(30/2)

s30=1140

Answer 2

The sum of the first 30 terms of the sequence –20, –16, –12, –8, –4, . . . is obtained being 1140

What is the sum of terms of an arithmetic sequence?

Arithmetic sequence is a sequence where each consequtive term has a common constant difference.

An arithmetic sequence, therefore, is defined by two parameters, viz. the starting term and the common difference.

Let the starting term be 'a' and common difference be 'd', then we get the arithmetic sequence as:

[tex]\rm a, a+d, a+2d, \cdots[/tex]

The sum of the first 'n' terms of that sequence is is:

[tex]\rm a + (a+d) + (a+2d) + \cdots + (a+(n-1)d) = \dfrac{n}{2}[2a + (n-1)d ][/tex]

For this case, the series –20, –16, –12, –8, –4, . . . starts from a = -20,

and each next term is obtained by adding d = 4 in previous term.

Thus, the sum of the first n = 30 terms of that sequence is evaluated as:
[tex]S_n = \dfrac{n}{2}[2a + (n-1)d ]\\\\S_{30} = \dfrac{30}{2}[2(-20) + (30-1)(4) ] = 15(-40 +116) = 15 \times 76 = 1140[/tex]

Thus, the sum of the first 30 terms of the sequence –20, –16, –12, –8, –4, . . . is obtained being 1140

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Related Questions

how many people in the town of summit have jobs if there are 9,255 people in the town and 1/3 of them are employed? simplify the fraction if possible ​

Answers

Answer:

divide 9,255 divide 1/3 and you will get your answer hope this helps :)))

Step-by-step explanation:

In the town of Summit, 3,085 people have jobs. If there are 9,255 people in the town and 1/3 of them are employed.

To find the number of people in the town of Summit who have jobs, we can multiply the total population by the fraction representing the employed individuals.

Total population = 9,255 people

Fraction employed = 1/3

Number of people employed = Total population * Fraction employed

Number of people employed = 9,255 * (1/3)

To simplify the fraction (1/3), we can divide both the numerator and denominator by their greatest common divisor, which is 1 in this case.

Dividing 1 and 3 by 1, we get:

1/1 = 1

3/1 = 3

So, the simplified fraction is 1/3.

Continuing the calculation:

Number of people employed = 9,255 * (1/3)

Number of people employed = 9,255 / 3

Number of people employed = 3,085

Therefore, in the town of Summit, 3,085 people have jobs.

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need help very badly i do not understand geometry lol

Answers

The third answer is correct!

Answer:

Step-by-step explanation:

sin 63 = JK/8

sin = opposite/hypotenuse

answer is C

Write an equation of the line that passes through the points (1, 2) and (4, 8)

Answers

Answer:

y = 2x

Step-by-step explanation:

The equation of a line in slope- intercept form is

y = mx + c ( m is the slope and c the y- intercept )

Calculate m using the slope formula

m = [tex]\frac{y_{2}-y_{1} }{x_{2}-x_{1} }[/tex]

with (x₁, y₁ ) = (1, 2) and (x₂, y₂ ) = (4, 8)

m = [tex]\frac{8-2}{4-1}[/tex] = [tex]\frac{6}{3}[/tex] = 2 , then

y = 2x + c ← is the partial equation

To find c substitute either of the 2 points into the partial equation

Using (1, 2 )

2 = 2 + c ⇒ c = 2 - 2 = 0

y = 2x ← equation of line

Answer:

2x-y=0 / y=2x

Step-by-step explanation:

6x-3y=0, 2x-y=0

need help can't figure it out​

Answers

Answer:

415

Step-by-step explanation:

Please help me (Trig) and show your work in the answer

Answers

Answer:

30.24 m

Step-by-step explanation:

Find the length of one of the braces b, use sine:

sin 55° = 6.2 / bb = 6.2 / sin 55° b = 7.56 m

Total length:

7.56*4 = 30.24 m

Pls help...................

Answers

First one b ≤ 9 good luck

Starbucks customers are complaining that a small cup of coffee at a local Starbucks coffee shop does not contain as much coffee as it should. On average, Starbucks claims that a small cup of coffee contains 360 grams of coffee. The customers decide to order 20 cups of coffee at random times; on average their cups contained 356 grams, and a standard deviation of 9 grams.

Required:
What is the null hypothesis?

Answers

Sharks exhibit a great diversity in their reproductive modes. There are oviparous (egg-laying) species and viviparous (liv

you have 4 ice cubes in your cup of lemonade. each ice cube has a length of 7 3/4 cm, a width of 4 5/8 cm and a height if 2 4/5 cm. what is the total volume of all ice cubes? explain how you used math to come to your decision.​

Answers

Answer:

how is this Spanish

Step-by-step explanation:

(90 POINTS SHOW YOUR WORK!!!) Determine the equation of the line that goes through points (-2, 1) and (1, -1)

Answers

(-1,1) is the correct answer.

Answer:

we have

(y-y1)/(x-x1)=(y2-y1)/(x2-x1)

(y-1)/(x--2)=(-1-1)/(1--2)

(y-1)/(x+2)=(-2)/3

3(y-1)=(-2(x+2))

3y-3=-2x-4

2x+3y-3+4=0

2x+3y+1=0 is a required equation

I need help please in my homework 100 point question

Answers

Answer:

5,000? what does it want me to find

Step-by-step explanation:

Solve x - 9 = 3 + y for y.

Answers

Step-by-step explanation:

[tex]x - 9 - 3 = y \\ y = x - 12[/tex]

The given equation solved for y as x-12.

The given equation is x-9=3+y.

What is an equation?

In mathematics, an equation is a formula that expresses the equality of two expressions, by connecting them with the equals sign =.

The given equation can be solved as follows:

x-9=3+y

⇒y=x-9-3

⇒y=x-12

Therefore, the given equation solved for y as x-12.

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A fraction is shown. 8/16 Which expression is equivalent to this fraction?

Answers

Answer:

1/2

Step-by-step explanation:

PLEEEEEEEEAAAAAAAAAAAASEEEEEEE HELP
What is 1/7 as a decimal rounded to the nearest 100th

Answers

It should be 0.14 if I’m not wrong

Triangle Inequalities part 2 help please

Answers

Answer:

The perimeter can not be 26 inches

Step-by-step explanation:

Given

[tex]Side\ 1 =19[/tex]

[tex]Side\ 2 =16[/tex]

Required

Is a perimeter of 26 possible?

First, calculate the possible side 3

[tex]Side\ 3 = Perimeter - Side\ 1 - Side\ 2[/tex]

[tex]Side\ 3 = 26 - 16 - 19[/tex]

[tex]Side\ 3 = -9[/tex]

The side length can not be negative.

So, the perimeter can not 26 inches

Mr. Robinson has raised $900 for his St. Baldricks campaign to fund childhood cancer research. This is 60% of his fundraising goal. What is Mr. Robinson's fundraising goal? pls give answer asap! :)

Answers

Answer:

1500

Step-by-step explanation:

STEP 1 900 = 60% × Y

STEP 2 900 =

60

100

× Y

Multiplying both sides by 100 and dividing both sides of the equation by 60 we will arrive at:

STEP 3 Y = 900 ×

100

60

STEP 4 Y = 900 × 100 ÷ 60

STEP 5 Y = 1500

It 1500 I hope it helps

which property justifies the statement below?
a(2b+c)=a(c+2b)

a. commutative property of addition
b. commutative property of multiplication
c. associative property of addition
d. distributive property

Answers

a

asta e raspunsul

gyyy

Divide the given polynomial by the given monomial.​

Answers

Answer:

Here are the answers. Need to have 20 characters for answer. Phew

A certain disease has an incidence rate of 0.7%. If the false negative rate is 5% and the false positive rate is
3%, compute the probability that a person who tests positive actually has the disease.
Give your answer accurate to at least 3 decimal places

Answers

I think it will be 3.7%hope it’ works

Find the missing length of the triangle.

Answers

Answer:

89

Step-by-step explanation:

Hypotenuse = sqrt[ (Leg a)2 + (Leg b)2 ]

Hypotenuse = sqrt[ (39)2 + (80)2 ]

Hypotenuse = sqrt[ 1521 + 6400 ]

Hypotenuse = sqrt[ 7921 ]

Hypotenuse = 89

Answer:

45 is your answer c=45 13

What equation can be used to find the earnings

Answers

29•(30/5) = $174.00.

6.62 X 0.7= 2.68 X 1.35

Answers

Answer:

3.934 = 3.634; hope this helps........

Step-by-step explanation:

Solve:

Multiply the numbers

5.62 ⋅ 0.7 = 2.68 ⋅ 1.35

3.934 = 2.68 ⋅ 1.35

Multiply the numbers

3.934 = 2.68 ⋅ 1.35

3.934 = 3.618

Result

3.934 = 3.618

The input is a contradiction: it has no solutions

Pls help! How do i Graph 4y = -3x - 8. explain the steps

Answers

Answer:

Step-by-step explanation:

to make a graph, when you have the equations, as you do,  just make up a table of some x coordinates,  you get to choose which ever ones you want so pick some easy ones,   like - 2,-1 , 0, 1, 2  .. then put each of those numbers into your equations as the x ... one at a time, ofc,   and see what you get out for y.  then you have the y coordinate of your table  

when you have your table then you can plot each of the points,  if you use the Demos  web site graphing tool you can make the graph on your computer , or use a graph paper.    

:)

Is(x+6)>8 is equation (with variable) give reason for your answer​

Answers

Answer:

it's a non equation if x=2 is given then we get a proper line of the equation bur x is greater than 2 the we find a region that go far from origin

a sphere of radius 10cm is to be turned out on a lathe. If the radius is made 0.1cm too long, what is the precentage of error made in the surface area of the sphere

Answers

Answer:

The percentage error is 8%

Step-by-step explanation:

Given

[tex]r = 10cm[/tex]

[tex]\triangle r =0.1cm[/tex]

Required

% error in the surface area

The surface area of a sphere is:

[tex]S = \4\pi r^2[/tex]

Differentiate

[tex]dS \approx 8\pi r\ dr[/tex]

Rewrite as:

[tex]\triangle S =8\pi r \triangle r[/tex] --- This represents the relative error

The percentage error is then calculated as:

[tex]\% Error = \frac{Relative\ Error}{Surface\ Area}[/tex]

[tex]\% Error = \frac{\triangle S}{S} * 100\%[/tex]

[tex]\% Error = \frac{8\pi r \triangle r}{\pi r^2} *100\%[/tex]

[tex]\% Error = \frac{8 \triangle r}{r} * 100\%[/tex]

[tex]\% Error = \frac{8 *0.1}{10} * 100\%[/tex]

[tex]\% Error = \frac{0.8}{10} * 100\%[/tex]

[tex]\% Error = 0.08 * 100\%[/tex]

[tex]\% Error = 8\%[/tex]

Help! I need to answer this on edge

Answers

your answer will be A

The function y=3x is growing slower than y=3^x

Step-by-step explanation:

hope it helps you

have a great day!!

Write a story problem for the equation 7z+4=32

Answers

Answer:

z=4

Step-by-step explanation:

7z+4=34

7x=32-4

7z=28

7z/7=28/7

z=4

Which is proportional

Answers

Answer:

B

Step-by-step explanation:

It goes up the same amount ($0.75) for every bar you get.

Please help- will give brainlist

Answers

I THINK it’s 33 because the other side is 41° and the other angle is the same forcept in this form ( x + 8 ) so i subtracted 8 from 41.

Which proportion can be used to find 20% of 17?​

Answers

Answer:

8.5

Step-by-step explanation:

Convert the percent to a decimal.

20% ÷ 100 = 0.2.

X = 17 ÷ 0.2.

X = 8.5

So 20% of 17 is 8.5.

The cashier determines that the customer's groceries total $156.75. If the sales tax is four percent, how much will the customer have to pay for their groceries, including tax?

Answers

156.75•.04 = 6.27 ||| 6.27+ 156.75 = $163.02
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