find the sum of the first 20 terms of the arithmetic sequence 4, -4, -12, -20​

Answers

Answer 1

Answer:

The sum of the first 20 terms is -1440.

Step-by-step explanation:

We want to find the sum of the first 20 terms of the arithmetic sequence:

4, -4, -12, -20...

The sum of an arithmetic sequence is given by:

[tex]\displaystyle S=\frac{k}{2}(a+x_k)[/tex]

Where k is the number of terms, a is the initial term, and x_k is the last term.

Since we want to find the sum of the first 20 terms, k = 20.

Our initial term a is 4.

Our last term is also the 20th term as we want the sum of the first 20 terms.

To find the 20th term, we can write an explicit formula for our sequence. The explicit formula for an arithmetic sequence is given by:

[tex]x_n=a+d(n-1)[/tex]

Where a is the initial term, d is the common difference, and n is the nth term.

Our initial term is 4. From the sequence, we can see that our common difference is -8 since each subsequent term is eight less than the previous term. Therefore:

[tex]x_n=4-8(n-1)[/tex]

Then the last or 20th term is:

[tex]x_{20}=4-8(20-1)=4-8(19)=-148[/tex]

Therefore, the sum of the first 20 terms are:

[tex]\displaystyle\begin{aligned} S_{20}&=\frac{(20)}{2}\left((4)+(-148))\\&=10(-144) \\&= -1440\end{aligned}[/tex]

Answer 2

Answer:

- 1440

Step-by-step explanation:

First-term is 4 and we subtract 8 to get the next term so the general term is

a(n) = 4 - 8(n -1)

The sum of the sequence is the average of the first and last terms multiplied by the number of terms: (a1 + an)/2 * n

We need the 20th term: a20 = 4 - 8(20–1) = 12 - 160 = - 148

The sum is (4 - 148)/2 * 20 = 10*(-144) = - 1440


Related Questions

Maya collected data about the number of ice cubes and milliliters of juice in several glasses of juice and organized the data into this table.

Ice Cubes 4 2 3 5 5 3 1
Juice (milliliters) 177 234 202 140 155 210 265

She used a graphing tool to display the data in a scatter plot, with x representing the number of ice cubes and y representing the milliliters of juice. Then she used the graphing tool to find the equation of the line of best fit:

y = -29.202x + 293.5.

Based on the line of best fit, approximately how many milliliters of juice will be in a glass with 7 ice cubes?

A.
10
B.
89
C.
118
D.
208

Answers

Answer:

Maya collected data about the number of ice cubes and milliliters of juice in several glasses of juice and organized the data into this table.

Ice Cubes 4 2 3 5 5 3 1

Juice (milliliters) 177 234 202 140 155 210 265

She used a graphing tool to display the data in a scatter plot, with x representing the number of ice cubes and y representing the milliliters of juice. Then she used the graphing tool to find the equation of the line of best fit:

y = -29.202x + 293.5.

Based on the line of best fit, approximately how many milliliters of juice will be in a glass with 7 ice

Step-by-step explanation:

Based on the line of best fit, approximately how many milliliters of juice will be in a glass with 7 ice.

Maya collected data about the number of ice cubes and milliliters of juice in several glasses of juice and organized the data into this table.

Ice Cubes             4        2      3        5       5      3        1

Juice (milliliters)  177    234   202   140   155   210   265

She used a graphing tool to display the data in a scatter plot, with x representing the number of ice cubes and y representing the milliliters of juice. Then she used the graphing tool to find the equation of the line of best fit:

y = -29.202x + 293.5.

What is the line of best fit?

A line of best fit refers to a line through a scatter plot of data points that best expresses the relationship between those points. Statisticians typically use the least-squares method to arrive at the geometric equation for the line, either through manual calculations or regression analysis software.

Based on the line of best fit, approximately how many milliliters of juice will be in a glass with 7 ice.

To learn more about the data visit:

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What are the steps in order of operations

Answers

Answer:

PEMDAS

Step-by-step explanation:

PEMDAS best identifies all of the steps in order of operation

where PEMDAS stands for parentheses exponents multiplication division addition and subtraction

Hope this helps!
PEMDAS .

P = Parentheses ( )
E = Exponents 2^2
M = Multiplication x
D = Division /
A = Addition +
S = Subtraction -

f(x)=2^x by a factor of five

Answers

Wdym please specify what you want to solve.

Solve 3 - x/2 > 15..



Answers

Answer:

x ≥-24

Step-by-step explanation:

3 - x/2 ≥ 15

Subtract 3 from each side

3-3 - x/2 ≥ 15-3

-x/2 ≥12

Multiply by -2

-x/2 * -2 ≥12 *-2

x ≥-24

Answer:

A. x ≤ 24

Step-by-step explanation:

[tex] \small \sf \: 3 - \frac{x}{2} ≥ 15 \\ [/tex]

multiply both side by 2 . Since 2 is the positive the inequality direction remains the same.

6 - x ≥ 30

subtract 6 from both sides

6 - 6 - x ≥ 30 - 6 -x ≥ 24

Divide both side by - 1. Since -1 is negative, the inequality direction remains the change.

x ≤ -24

The Marked price, inclusive of GST, of a notebook computer is $1679.90.it is sold at a discount of 10%.
a) find its marked price before GST
b)Find the GST before discount.
c)What is the selling price of the computer
d) find the GST after the discount
e)what is the percentage decrease in the GST

Answers

Answer:i don’t know

Step-by-step explanation:i don’t know

This year, Carlos planted 6 more than one-third of the cucumber plants he planted last year. How many cucumber
plants did he plant this year if last year he planted 12 plants?
6
9
10
12? PLEASE HELP SMB

Answers

Answer:

10 plants

Step-by-step explanation:

Answer:

10

Step-by-step explanation:

He planted 10 this year because last year he planted 12, and 1/3 of that is 4. He planted 6 more than that this year, so 4+6=10.

Tamisha's shampoo bottle holds 1/2 bottle of shampoo.She used 5/6 of the bottle.How many gallons of shampoo has Tamisha used?

Answers

Answer:

5/12

Step-by-step explanation:

1/2 x 5/6 = 5/12

A car with a passenger of mass 56 kg can travel a distance of 120 km using 10 l of petrol. If the number of passengers increases to 4 people with a total mass of 224 kg, the distance travelled decreases by 10%.
What is the total distance that the car carrying 4 passengers can travel using 10 l of petrol?​

Answers

Answer:

120 * 0.90 = 108 km

Step-by-step explanation:

Answer:

108km

Step-by-step explanation:

The distance traveled (in meters) by a frog is modeled by the equation d=2t where d is the distance traveled in meters and t is the time in minutes. Find the distance traveled in 25 minutes.

Answers

Given,

d = 2t

here, t = 25

Therefore,

d = 2*25

= 50m

Need help on this!! 10 points!!!

Answers

Answer:

The answer is B

I need help please!!!

Answers

Answer:

40 degrees

Step-by-step explanation:

Help!!

Marta is solving the equation S = 2πrh + 2πr2 for h. Which should be the result?

StartFraction S Over 2 pi r EndFraction equals h. – r = h
StartFraction S minus r Over 2 pi r EndFraction equals h. = h
S – S minus StartFraction r Over 2 pi EndFraction equals h. = h
S – S minus StartFraction 2 pi Over r EndFraction equals h. = h

Answers

Answer:

(S-2πr^2)/ 2πr = h

Step-by-step explanation:

S = 2πrh + 2πr^2

Subtract 2 pi r^2 from each side

S-2πr^2  = 2πrh + 2πr^2 -2πr^2

S-2πr^2  = 2πrh

Divide each side by 2 pi r

(S-2πr^2)/ 2πr = 2πrh/2πr

(S-2πr^2)/ 2πr = h

It is given that,

→ S = 2πrh + 2πr²

Now subtract 2πr² from the both sides,

→ S - 2πr² = 2πrh + 2πr² - 2πr²

→ S - 2πr² = 2πrh

Then divide both sides by 2πr,

→ (S-2πr²)/2πr = 2πrh/2πr

→ (S-2πr²)/2πr = h

Hence, (S-2πr²)/2πr = h is the result.

Jacob Sketched a floor plan for a new two room clubhouse . In his sketch each centimeter was equal to 1.5 feet . The largest room on his clubhouse plan measured 6.2 cm by 7.4 cm. How many square feet would the actual room be? Round you answer to the nearest hundredth.

Answers

Answer:

103.23 square feet

Step-by-step explanation:

Area of the largest room = length × width

Each centimeter was equal to 1.5 feet

7.4 cm = 1.5 × 7.4 = 11.1 feet

6.2 cm = 1.5 × 6.2 = 9.3 feet

Length = 11.1 feet

Width = 9.3 feet

Area of the largest room = length × width

= 11.1 feet × 9.3 feet

= 103.23 square feet

Flying against the wind, a jet travels miles in hours. Flying with the wind, the same jet travels miles in hours. What is the rate of the jet in still air and what is the rate of the wind

Answers

Answer:

Velocity in still air: 760 mi/ hr

Velocity against the wind: 210 mi/ hr

Step-by-step explanation:

Given

See attachment for complete question

Required

The rate in still air

The rate of the wind

From the question, the velocity (v) against the wind is:

[tex]v =\frac{distance}{time}[/tex]

[tex]v =\frac{3040}{4}[/tex]

[tex]v_1 =760mi/hr[/tex]

The velocity with the wind is:

[tex]v_2 = \frac{8260}{7}[/tex]

[tex]v_2 = 1180mi/hr[/tex]

Let:

[tex]x \to[/tex] velocity in still air

[tex]y \to[/tex] velocity of the wind

So, we have:

[tex]x - y = 760[/tex]

[tex]x + y = 1180[/tex]

Add both equations

[tex]x + x -y + y = 760 + 1180[/tex]

[tex]2x = 1940[/tex]

Divide by 2

[tex]x = 970[/tex]

Substitute [tex]x = 970[/tex] in [tex]x - y = 760[/tex]

[tex]970 - y= 760[/tex]

Make y the subject

[tex]y = 970 - 760[/tex]

[tex]y = 210[/tex]

Explain what you would do first to simplify the expression below. Justify why, and then state the result of performing this step.

Answers

Remember PEMDAS, you have to simplify the exponent first.

2. A rectangle has length 13 and width 10. The length and the width of the rectangle are each
increased by 2. By how much does the area of the rectangle increase? *
50
20
38
35

Answers


TRUST ME :



The answer above is correct !!


Question 1: Use the image and your knowledge of the isosceles triangle to find the value of x

Answers

Answer:

35 degrees

Step-by-step explanation:

since both sides are equal, so are the angles involved.

Can someone help me with this math homework please!

Answers

Answer:

-1

Step-by-step explanation:

we match the input to the output to find that f(3) points towards -1

Multiplicar:

a. (– 6) (– 7) =

b. – 12 x – 5 =
c. (+ 10) (– 6) =
d. (– 15) (+ 5) =
e. (+ 11) (+6) =
f. (– 3) (– 5) (– 6) =
g. (– 8) (+6) (-3) =
h. (- 5) (+ 3) (+9) =

Answers

Answer:

a. 42

b. -12x-5

c. -60

d. -75

e. 66

f. -90

g. 144

h. -135

in a two digit number the tens digit is 6 more than the units digit. if the digits are interchanged, the sum of the new and the original number is 132. Determine the original number.​

Answers

Given:

In a two digit number the tens digit is 6 more than the units digit.

If the digits are interchanged, the sum of the new and the original number is 132.

To find:

The original number.

Solution:

Let the unit digit of the original number be x. So, the tens digit is (x+6) and the value of the number is:

[tex]m=(x+6)\times 10+x\times 1[/tex]

[tex]m=10x+60+x[/tex]

[tex]m=11x+60[/tex]

If we interchange the digits, then the value of new number is:

[tex]n=x\times 10+(x+6)\times 1[/tex]

[tex]n=10x+x+6[/tex]

[tex]n=11x+6[/tex]

The sum of the new and the original number is 132.

[tex]m+n=132[/tex]

[tex]11x+60+11x+6=132[/tex]

[tex]22x+66=132[/tex]

[tex]22x=132-66[/tex]

[tex]22x=66[/tex]

Divide both sides by 22.

[tex]x=\dfrac{66}{22}[/tex]

[tex]x=3[/tex]

So, the unit digit of the original number is 3 and the tens digit is:

[tex]x+6=3+6[/tex]

[tex]x+6=9[/tex]

Therefore, the original number is 39.

What is the word form of 0.604

Answers

Answer:

zero point six hundred and four

Step-by-step explanation:

Which property would allow you to use mental computation to simplify the problem 27 + 15 + 3 + 5?

Answers

Answer:

commutative property of addition.

a sequence of additions can be done in any order and the total remains the same.

Step-by-step explanation:

so, we can actually do

27 + 3 + 15 + 5

and now it is easy to combine 27+3 to 30 and 15+5 to 20, and to make the final calculation of 30 + 20 = 50 in our minds.

Which equation will solve the following word problem? There are 36 tables and 7 booths in the family restaurant. Each table seats 4 people. If the restaurant can seat up to 184 people, what is the capacity of each booth?


(B * 7 ) - (36 * 4) = 184


7B + (36 * 4) = 184


184 - (36 * 4) = B/7


184/4 = B * 7

Answers

Answer:

7B + (36 * 4) = 184

Step-by-step explanation:

In a family restaurant there are 36 tables and 7 booths.

Each table can seat 4 people.

Let the number of people who can be seated in a booth be represented by B.

Total seating capacity of the restaurant is 184 people.

Expressing this as an equation:

Among the given options, this relation is expressed in the second option, namely, 7B + (36 * 4) = 184

How is mathematical thinking established? How can we have mathematical thinking?

修改翻译结果

Answers

All I see are the two questions and either mandarine or Japanese

Translate How is mathematical thinking established? How can we have mathematical thinking? in to Chinese.

数学思维是如何建立的? 怎样才能有数学思维?

Find the area of the parallelogram

Answers

Answer:

The answer is 32.

Step-by-step explanation:

Just multiply the height by the base length. 4*8=32

Complete the remainder of the
table for the given function rule:
y = 3x - 8
X | -4 -2 0 2 4
y -20 [?] [ ] [ ] [ ]

Answers

The values that complete the table are -14, -8, -2 and 4

Function rule

Given the function y = 3x - 8, we are to complete the given table.

If x = -2

y = 3(-2) - 8

y = -14

If x = 0

y = 3(0) - 8

y = -8

If x = 2

y = 3(2) - 8

y = -2

If x = 4

y = 3(4) - 8

y = 4

Hence the values that complete the table are -14, -8, -2 and 4

Learn more on table of functions here: https://brainly.com/question/3632175

Can you help with 7-10

Answers

Answer:

7.Mean=Ex/n

= 88+96+92+84+86+92+98/7

=90

(b). Median = {84,86,88},92,{92,96,98}

=92

(C).Mode=92 ; it is the number with the highest frequency

9.Mean=Ex/n

=28+26+32+24+27+32+29/7

=28

(b).Median={24,26,27},28,{29,32,32}

=28

(c).Mode=32;it is the number with the highest frequency.

8.Mean=Ex/n

=3.5+5.7+9.8+7+12.4+10.2/6

=8.1

(b).Median={3.5,5.7},7,9.8,{10.2,12.4}

=7+9.8/2

=8.4

(c).Mode=no mode

10.Mean=Ex/n

=2+6+9+8+8+2+8+7+5+4/10

=5.9

(b).Median={2,2,4,5},6,7,{8,8,8,9}

=6+7/2

=6.5

(c).Mode= 8;it is the number with the highest frequency.

I hope this helps.

Can someone please help me! Big ideas number 22 8.4

Answers

Answer:

26

Step-by-step explanation:

the whole area is the sum of the area of the rectangle in the middle and the 2 triangles on either side of the rectangle.

sBC = distance between (0,3) and (4,-1)

and that is the Pythagoras calculation with the coordinate differences

sBC² = (4-0)² + (-1 - 3)² = 16 + 16 = 32

sBC = sqrt(32) = sFE

to get the area of the rectangle we need also FB (or CE).

sFB² = (0 - -2)² + (3-1)² = 4 + 4 = 8

sFB = sqrt(8) = sCE

area of rectangle is

sBC×sFB = sqrt(32)×sqrt(8) = sqrt(32×8) = sqrt(256) = 16

the area of a right-angled triangle is

a×b/2

we have sFB and need sAF

sAF² = (-5 - -2)² + (4-1)² = 9 + 9 = 18

sAF = sqrt(18)

the area of the left triangle is

sFB×sAF/2 = sqrt(8)×sqrt(18)/2 = sqrt(8×18)/2 = sqrt(144)/2 = 12/2 = 6

for the right triangle we have sCE and need sED.

sED² = (2 - 4)² + (-3 - -5)² = 4 + 4 = 8

sED = sqrt(8)

the area of the right triangle is

sCE×sED/2 = sqrt(8)×sqrt(8)/2 = 8/2 = 4

so in total we have for the area

16 + 6 + 4 = 26

m-2n = 8
n = m - 2
The value of m in the system of equations is:

Answers

Answer: m= -4


Step 1: Substitute information

To solve this we will use the substitution method. This means that we will use the information provided to us in the second equation, and substitute it into the first equation. We are told what n equals, so let’s substitute this now.

m-2n=8
m-2(m-2)=8

Step 2: Distribute

Now that we have substituted the information, let’s distribute. This means that we will multiply the numbers on the outside of the parentheses with the numbers on the inside of the parentheses. Let’s do this now.

m-2(m-2)=8
m-2m+4=8

Step 3: Combine like terms

Now that we have distributed, we can continue solving the problem. The next step is to combine like terms. This means to combine terms with the same variable, or lack of. In this case, that is m and -2m.

m-2m+4=8
-m+4=8

Step 4: Get variable alone on the left side

We can now work to get the variable alone on the left side. We can do this by moving the number on the right side, in this case by adding 4 on both sides.

-m+4=8
-m=4

Step 5: Make m positive

In this final step, we must work to make m positive. We can do this by multiplying each term by -1. This will make m positive, and 4 negative. Let’s do this now.

-m=4
-1(-m)= -1(4)
m= -4

This is your answer! M is equal to -4. Hope this helps! Comment below for more questions.

HELP ASAP!!!

The circle graph shows the percentage of visitors at a
convention who ordered various flavors of juice. There were 700
visitors at the convention.
About how many visitors ordered grape juice or apple juice?
Enter your answer in the box.


Answers

Step-by-step explanation:

40+24+11+8+17= 100

100 - 700

24 - ?

24×700/100

= 168 visitors ordered apple juice

100-700

11-?

11×700/100

=77 people ordered grape juice

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