What is the first term of a 14-term arithmetic sequence where the last term is −12 and the sum is 42?
A. 6
B. 7
C. 13
D. 18

please explain answer

Answers

Answer 1
Answer:  D) 18

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

Work Shown:

Here are the variables we're working with

a = first termb = last term (aka nth term)n = number of termsS = sum of the first n terms

In this case, we know that

a = unknown (what we want to solve for)b = -12 n = 14S = 42

We can use this formula to help find the answer

S = (n/2)*(a+b)

This formula only works for arithmetic sequences

So,

S = (n/2)*(a+b)

42 = (14/2)*(a+(-12))

42 = 7(a-12)

42/7 = a-12

6 = a-12

6+12 = a

18 = a

a = 18 is the first term of this arithmetic sequence

That's why the answer is choice D.

-----------

Side note: your book or your teacher may use the notation [tex]S_n = \frac{n}{2}(a_1+a_n)[/tex] but I figured it would be easier to use 'a' and b in place of [tex]a_1[/tex] and [tex]a_n[/tex] respectively.


Related Questions

Write the following geometric sequence recursively: 10, 100, 1000, 10000.*

Answers

Answer:

i think the * is 100000, each number times 10

it would be letter A i hope this really helped you have a blessed day

Plz help me well mark brainliest if correct....??????????????...

Answers

Answer:

D). 100

Step-by-step explanation:

The range is the highest number-lowest number in data. 150 is the highest, 50 is the lowest. Therefore, 150-50=100

Suck please help thanks

Answers

Yea what he said :) :) :) he’s right

Rationalise
[tex]{ \frac{1 + \sqrt{3} }{ \sqrt{12} } } [/tex]

Answers

Answer:

Step-by-step explanation:

Answer:

[tex]\frac{2\sqrt{3} + 6}{12}[/tex]

Step-by-step explanation:

Simplify the denominator of [tex]\frac{1 + \sqrt{3} }{\sqrt{12} }[/tex] completely.

[tex]=> \frac{1 + \sqrt{3} }{ \sqrt{(4 \times 3)} } = \frac{1 + \sqrt{3} }{\sqrt{4} \times \sqrt{3} } = \frac{1 + \sqrt{3} }{2\sqrt{3} }[/tex]

Now, to rationalise it you need to make the denominator rational.

Multiply & divide [tex]\frac{1 + \sqrt{3} }{2\sqrt{3} }[/tex] by [tex]2\sqrt{3}[/tex].

[tex]=> \frac{1 + \sqrt{3} }{2\sqrt{3} } \times \frac{2\sqrt{3} }{2\sqrt{3} }[/tex]

[tex]=> \frac{(1 + \sqrt{3})\times 2\sqrt{3} }{2\sqrt{3} \times 2\sqrt{3} }[/tex]

[tex]=> \frac{2\sqrt{3} + 6 }{12}[/tex]


Pls help me on this due today plssss!!!

Answers

Answer:

Step-by-step explanation:

A+B+C+D=360 degree (being one complete turn)

360 degrees

Step-by-step explanation:

because it a venticular angle you one side(180) and the other side (180) given you 360 degrees

what is the probability of seeing a sample mean for 21 observations less or equal to the sample mean that we observed

Answers

Answer:

[tex]P(x \le 21) = 0.69146[/tex]

Step-by-step explanation:

The missing parameters are:

[tex]n = 64[/tex] --- population

[tex]\mu = 20[/tex] --- population mean

[tex]\sigma = 16[/tex] -- population standard deviation

Required

[tex]P(x \le 21)[/tex]

First, calculate the sample standard deviation

[tex]\sigma_x = \frac{\sigma}{\sqrt n}[/tex]

[tex]\sigma_x = \frac{16}{\sqrt {64}}[/tex]

[tex]\sigma_x = \frac{16}{8}[/tex]

[tex]\sigma_x = 2[/tex]

Next, calculate the sample mean [tex]\bar_x[/tex]

[tex]\bar x = \mu[/tex]

So:

[tex]\bar x = 20[/tex]

So, we have:

[tex]\sigma_x = 2[/tex]

[tex]\bar x = 20[/tex]

[tex]x = 21[/tex]

Calculate the z score

[tex]x = \frac{x - \mu}{\sigma}[/tex]

[tex]x = \frac{21 - 20}{2}[/tex]

[tex]x = \frac{1}{2}[/tex]

[tex]x = 0.50[/tex]

So, we have:

[tex]P(x \le 21) = P(z \le 0.50)[/tex]

From the z table

[tex]P(z \le 0.50) = 0.69146[/tex]

So:

[tex]P(x \le 21) = 0.69146[/tex]

Which answers describe the shape below

Answers

Answer:

B. parallelogram

Step-by-step explanation:

stay safe, stay healthy and blessed.

thank u

Answer:

a b c d e

Step-by-step explanation:

PLEASE HELP GUYS I’m being timed

Answers

The question is the base of the triangle, so we use the formula : b²=c²–a²

——————————————————————

[tex] {b}^{2} = \sqrt{c^{2} - {a}^{2} }[/tex]

[tex] {b}^{2} = \sqrt{ {16}^{2} - {8}^{2} } [/tex]

[tex] {b}^{2} = \sqrt{256 - 64} = \sqrt{192} [/tex]

[tex] \sqrt{192} =8 \sqrt{3} [/tex]

Find the equation of the linear relationship.

Answers

Answer:

y = -3x + 150

Step-by-step explanation:

2 points on the graph:

(30, 60) and (40, 30)

Slope:

m=(y2-y1)/(x2-x1)

m=(30 - 60)/(40 - 30)

m= (-30)/10

m= -3

Slope-intercept:

y - y1 = m(x - x1)

y - 60 = -3(x - 30)

y - 60 = -3x + 90

y = -3x + 150

Jon Deposits $14,500 into an account paying 5% annual interest compounded quarterly and Sara deposits $16,250 into an account paying 4% annual interest compounded daily who will have more money after 1 year? How much more will that person have? Show and explain all work.

Answers

Answer:

Results are below.

Step-by-step explanation:

Giving the following information:

Jon:

Initial investment (PV)= $14,500

Interest rate (i)= 0.05/4= 0.0125

Number of periods (n)= 4 quarters

Sara:

Initial investment (PV)= $16,250

Interest rate (i)= 0.04/365= 0.00011

Number of periods (n)= 365 days

To calculate the Future Value, we need to use the following formula:

FV= PV*(1+ i)^n

Jon:

FV= 14,500*(1.0125^4)

FV= $15,238.71

Sara:

FV= 16,250*(1.00011^365)

FV= $16,915.67

Sara will have $1,676.96 more than Jon.

A company's daily cost c, in hundreds of r dollars, to manufacture n items of a certain product can be modeled by the function c^-1(5)=80, Lording to the model, which of the following is the best interpretation of c ^1(5) = 80, where c^1 is the inverse function of c ?
a) The company's daily cost to manufacture 5 items of the product is $80.
b) The company's daily cost to manufacture 5 items of the product is $8,000.
c) The company's daily cost to manufacture 500 items of the product is $80.
d) The company's daily cost to manufacture 80 items of the product is $5.
e) The company's daily cost to manufacture 80 items of the product is $500.

Answers

Answer:

e) The company's daily cost to manufacture 80 items of the product is $500.

Step-by-step explanation:

We have that:

c is the cost in hundreds of dollars to manufacture n items. The input is the number of items, and the output is the cost, in hundreds of dollars.

Inverse function:

In the inverse function, the input and the output are exchanged from the original function, that is, in this situation, the input in the cost, in hundreds of dollars, and the output is the number of manufactured items.

c^-1(5)=80

Input of the inverse function is 5, which is the cost, in hundreds of dollars, that is, $500, to manufacture 800 itens. This means that the correct answer is given by option e.

Ecuaciones
A: 7=5-×
B: ×-2=-16
C: -8=4.×
D: ×.2=-6

Answers

Step-by-step explanation:

A:x=5-7

x=-2

B:x=-16+2

x=-14

l have answered only A and B

y is directly proportional to the positive square root of x when x = 9, y= 12 find y when x =1/2​

Answers

Y =k√x

12 = 3k

k = 4

now X = 1\2

y = 4√1/2

y = 2√2

Answer:

y = 2[tex]\sqrt{2}[/tex]

Step-by-step explanation:

Given y is directly proportional to [tex]\sqrt{x}[/tex] then the equation relating them is

y = k[tex]\sqrt{x}[/tex] ← k is the constant of variation

To find k use the condition when x = 9, y = 12

12 = k[tex]\sqrt{9}[/tex] = 3k ( divide both sides by 3 )

4 = k

y = 4[tex]\sqrt{x}[/tex] ← equation of variation

When x = [tex]\frac{1}{2}[/tex] , then

y = 4[tex]\sqrt{\frac{1}{2} }[/tex] = 4 × [tex]\frac{1}{\sqrt{2} }[/tex] ← rationalise the denominator by multiplying by [tex]\frac{\sqrt{2} }{\sqrt{2} }[/tex]

y = [tex]\frac{4}{\sqrt{2} }[/tex] × [tex]\frac{\sqrt{2} }{\sqrt{2} }[/tex] = [tex]\frac{4\sqrt{2} }{2}[/tex] = 2[tex]\sqrt{2}[/tex]

1 out of 5 pairs of Henry's shoes no longer fit him. what fraction of his shoe collection still fit ?​

Answers

the answer is 4/5.

hope this helps!!

Answer:

4/5

Step-by-step explanation:

here ya are. I hope this helps, it's just 1 pair out of the 5 that don't fit. Meaning the 4 out of 5 fit. therefore 4/5

The 7th grade class is going on a trip to Disneyland there are 162 learners and 24 LF's attending the trip one bus can hold 65 people how many buses do they need to order to take everyone to Disneyland

Answers

Answer: about 3 buses

Step-by-step explanation: 162+24=186 and 65*3=195 so 3 buses is enough

Hope this helps:)

Factor the expression below.
x² - 64
O A. (x - 16)(x-4)
B. (x+16)(x-4)
O C. (x-8)(x-8)
O D. (x+8)(x-

Answers

Answer:

(x-4)(x+4)

Step-by-step explanation:

x^2 - 64 = x^2 - 4^2 = (x-4)(x+4)

a recipe for 24 bran muffins requires 2.25 cups of flour. You want to make 30 bran muffons. which proportion could be solved to find x, the total number of cups of flour needed

Answers

Answer:

Number of cups water require for 30 muffins = 2.82 cups (Approx.)

Option "D"

Step-by-step explanation:

Given:

24 bran muffins required = 2.25 cups of flour

Find:

Number of cups water require for 30 muffins

Computation:

Assume;

Number of cups water require for 30 muffins = x

So,

24 / 2.25 = 30 / x

x = [30 × 2.25] / 24

x = 67.65 / 24

x = 2.8187

Number of cups water require for 30 muffins = 2.82 cups (Approx.)

What is the measure of remote angle, ∠A?

Answers

Answer:

40

Step-by-step explanation:

Inscribed Angle =  1/2 Intercepted Arc

<A = 1/2 (80)

<A = 40

What is : X + -3 = -10

Answers

Step-by-step explanation:

add 3

x = - 7___________..........

x = -7
move the 3 after the 10 which becomes
x = -10+3
calculate the -10+3 which equals -7



Precision is a measure of how close an answer is to the actual or expected
value.
True or false ?

Answers

i’m pretty sure it’s true

Answer:

False

Step-by-step explanation:

Precision  describes repeatability.  

Accuracy  describes the closeness of a measurement to the actual value.

 So your measurements may be precise but not accurate; for example if you used a faulty measurement system. And of course, you could get accurate results SOME of the time (which describes the exprerience of most researchers).

Errors in precision are usually detected.........eventually, invariably after you have shot your mouth off to your professor.

What is the product?
2 3 4
5 9 -1 -7
11 5 -3

Answers

Answer:

-1247400

Step-by-step explanation:

See the Image below:) I believe this is what you are looking for.

A man-made lake is stocked with 10,000 fish. This population is expected to decline by an annual rate of 12%
Predict the fish population 5 years after the lake is stocked

Answers

Answer:

4000 fish left in lake after 5 years

Step-by-step explanation:

12 x 5 = 60 (60%)

10000 - 60% = 4000

If the surface area of the cone below is 628.32 m², find its volume.


I WILL MARK BRAINLEIST IF CORRECT AND 20 POINTS

Answers

Answer:

1586.91 m³

Step-by-step explanation:

From the diagram attached,

Applying,

A = πrl.................. Equation 1

Where A = surface area of the cone, l = slight heigth of the cone, π = pie.

make l the subject of the equation,

l = A/πr.............. Equation 2

From the question,

Given: A = 628.32 m², π = 3.14, r = 8 m

Substitite these values into equation 2

l = 628.32/(3.14×8)

l = 25 m

But,

l² = h²+r².................... Equation 3

Where h = height of the cone.

h = √(l²-r²)

h = √(25²-8²)

h = √(625-64)

h = √(561)

h = 23.69 m

Also Applying,

V = 1/3πr²h

Where V = volume of the cone.

Therefore,

V = (3.14×8²×23.69)/3

V = 1586.91 m³

Juan family hang their clothes outside to dry, if they use the dryer, there $400 monthly bill will increase by % wich means it will cost $700

Answers

75%
Hope this helps :D
I can also explain if you need help

Reflect (1,‐4) across the x‐axis what is the reflected ordered pair?​

Answers

Answer:

(1,4)

Step-by-step explanation:

(1,-4) is over 1 and down negative 4 so reflected over the x-axis(the horizontal one) it would be four up so the answer is (1,4)

Answer: (1,4)

Step-by-step explanation:

The rule for reflecting over the X axis is to negate the value of the y-coordinate of each point, but leave the x-value the same. For example, when point P with coordinates (1,-4) is reflecting across the X axis and mapped onto point P', the coordinates of P' are (1,4)

Find the graph of the inequality y+2>-3(x+1)

Answers

Answer:

Below.

Step-by-step explanation:

y + 2 > -3(x + 1)

y + 2 > -3x - 3

y > -3x - 5

The graph will be the graph of the line y = -3x - 5 (dotted line),  with the area above the line shaded.

2 Which of the following is true about rhombus LMNO?​

Answers

Rhombus LMNO is shown with its diagonals.

Rhombus L M N O is shown. Diagonals are drawn from point M to point O and from point L to point N and intersect at point P. All sides are congruent.

Angle MLO measures 112°. What is the measure of angle MLP?

45°

56°

68°

90°

Step-by-step explanation:

B

Type the correct answer in the box.
Consider the system of linear equations below.
-3x+4y=24
6x+2y=-18

Answers

Answer:

[tex] - 3x + 4y = 24 \\ 3x - 4y = - 24 - - - (a) \\ 6x + 2y = - 18 - - - (b) \\ 2 \times (a) - (b) : \\ = > 0x - 10y = - 30 \\ 10y = 30 \\ y = 3 \\ \\ 3x = - 12 \\ x = - 4 \\ { \boxed{x = - 4}} \: \: \\ { \boxed{y \: = \: 3}}[/tex]

RUNNING OUT OF POINTS PLEASE!! Find the perimeter and area for the triangle. Be sure to write the formula, and use correct measure. ​

Answers

Answer:

Area = 77ft²

Perimeter = 44 9/20 feets

Step-by-step explanation:

Area of a triangle = 1/2 * base * height

Base = 19 1/4 feets = 77/4 feets

Height = 8 feets

Area = 1/2 * 77/4 * 8

Area = (77 * 8) / 8

Area = 77 feet²

Perimeter of a triangle :

Sum of the sides

Perimeter = a + b + c

Perimeter = 19 1/4 + 10 + 15 1/5

Perimeter = 44 + (1/4 + 1/5)

Perimeter = 44 9/20

Help me PLEASEEEEEEEEEEEEE

Answers

Answer:

D. 144

Step-by-step explanation:

Find volume of shipping container:

2 2/3 = 8/3

2 x 1 = 2

8/3 x 2/1 = 16/3

Find volume of cube:

1/3 x 1/3 = 1/9 x 1/3 = 1/27

Find how many boxes fit in container:

16/3 ÷ 1/27

16/3 x 27/1

Simplify:

16/1 x 9/1 = 144/1

Answer: 144

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