pls help me to answer this​

Answer:

This sum is the sum of an arithmetic sequence.  There is a formula for the sum of an arithmetic sequence which can be looked up or derived by a variety of means.

A nice approach for this sequence is the following.  Notice  that the sum of first and last number in the sequence is the same as the sum of the second and second last, and also the same as the sum of the third and third last, and so on.

There are n of these pairs.  So the desired sum is n x (first number + last number).   But the first number is 1 and the last on is 2n.   Thus the desired sum is n(1 + 2n).

Hope this helps!!

Mark Brainleast!!!!!!!!!!!

Consider the set {1, 2, 3, 4, ..., m} where m is some natural number, i.e. a positive whole number.

Now let's say we wanted to add everything in that set.

What we can do is write out the terms

1, 2, 3, 4, ..., m

then just underneath, we write the reverse of that set

m, ..., 4, 3, 2, 1

Here's an example of what I mean. I'll use m = 7

[tex]\begin{array}{|c|c|c|c|c|c|c|} \cline{1-7}1 & 2 & 3 & 4 & 5 & 6 & 7\\\cline{1-7}7 & 6 & 5 & 4 & 3 & 2 & 1\\\cline{1-7}\end{array}[/tex]

For each column, add straight down

The third row will be nothing but 8's

[tex]\begin{array}{|c|c|c|c|c|c|c|} \cline{1-7}1 & 2 & 3 & 4 & 5 & 6 & 7\\\cline{1-7}7 & 6 & 5 & 4 & 3 & 2 & 1\\\cline{1-7}8 & 8 & 8 & 8 & 8 & 8 & 8\\\cline{1-7}\end{array}[/tex]

We can see there are seven copies of '8' being added here, so the sum of all the numbers in the set {1,2,3,4,5,6,7} is 8*7 = 56. But wait, we double-counted each item when we formed the second row. So we must divide by 2 to fix the double-counting error.

Therefore, 1+2+3+4+5+6+7 = 56/2 = 28 instead.

-----------------------------

That previous example showed that adding from 1 to 7 means we have 7 copies of (1+7). In other words, 7 copies of 8 being added.

We could write that as 7(1+7)

Then divide that by 2 to fix the double-counting error.

We have 7(1+7)/2

Now imagine that we applied all of what was mentioned to the set {1,2,3,4,5,6,7,8}. Instead of 7's, we use 8's this time to get 8(1+8)/2

Then we can extend it out to the set {1,2,3,4,..., m} and we get the formula m(1+m)/2

We have m copies of (1+m) being added; hence the m(1+m). Don't forget to divide by 2 to fix the double-counting error.

-----------------------------

The key takeaway here is that summing 1+2+3+4+...+m gets us m(1+m)/2

In this case, m = 2n because we want the first 2n natural numbers.

Therefore,

m(1+m)/2

2n(1+2n)/2

n(1+2n)

n(2n+1)

represents the sum 1+2+3+...+n+...+2n

-----------------------------

Try out a value like n = 5 to find that 2n = 2*5 = 10, and,

1+2+3+4+5+6+7+8+9+10 = 55

also

n(2n+1) = 5(2*5+1) = 5*(11) = 55

Showing that the formula works for n = 5. I'll let you try other values of n.

James should earn a weekly salary of $ 432.76 with 0 exemptions to give the closest exemption.

In this question, we should estimate the salary earned before one exemption and find the equivalent brute salary with no exemptions. The expected salary is equal to product the brute salary minus the product of the tax rate and brute salary.

According to the table we have the expected salary after one exemption:

[tex]x = 418\cdot \left(1-\frac{19.66}{100} \right)[/tex]

[tex]x = 335.82[/tex]

After a quick inspection to the salary column for zero exemptions, we find that percentage associated to a salary with no exemptions: ([tex]r = 22.40\,\%[/tex])

[tex]C = \frac{335.82}{1-\frac{22.40}{100} }[/tex]

[tex]C = 432.76[/tex]

James should earn a weekly salary of $ 432.76 with 0 exemptions to give the closest exemption. [tex]\blacksquare[/tex]

The exemption table is missing. The complete figure is shown below.

To learn more on salaries, we kindly invite to check this verified question: https://brainly.com/question/3315407

Answer:

we need more information

Let that be x

Use the general formula used for calculating half-life

[tex]\\ \rm\Rrightarrow A=A_o(0.5)^{\frac{t}{h}}[/tex]

put values

The equation is

[tex]\\ \rm\Rrightarrow A=90(0.5)^{x/17.5}[/tex]

Answer:

14/9 hours

Step-by-step explanation: 1/2+1/7=9/14, so 1/(9/14)=14/9

Answer:

27.7% of third year girls study biology

this is what would make sence for me

the frist one was confusing

Answer:

False

Step-by-step explanation:

Check if there is a right angle using the Pythagorean Theorem:

7.2^2 + 9.1^2 ≟ 12^2

134.65 ≠ 144,

so since there isn't a right angle, this is not a rectangle.

Answer: 55

Step-by-step explanation:

Angle VWX and the 55 degree angle are vertical angles.

Answer:

x= 3(y+8)/

8

y= 8(x-3)/

3

Answer:

3 hrs and 15 minutes :)

Step-by-step explanation:

We can solve this by multiplying :)

39 x 5 = 195 minutes

195/60 = 3 hrs and 15 minutes :)

Have an amazing day!!

Please rate and mark brainliest!!

Answer: 195 minutes or 3 hours and 15 mintues

Step-by-step explanation:

     We will multiply the number of tests by the amount of time it takes to do each test.

     39 total tests * 5 minutes = 195 minutes

           195 minutes or 3 hours and 15 mintues

The hypotenuse is the longer of the 3 sides:

answer: b.26

Answer:

[tex]\huge\boxed{\bf\: b. \: 26 \rightarrow hypotenuse }[/tex]

Step-by-step explanation:

Consider a right angled triangle with sides as 10, 26 & 24 units.

Here, we need to find the hypotenuse of the triangle.

The hyptenuse is the side which is opposite to the right angle (90°) & is also the longest side of the triangle.

Then, among the given values, we can clearly say that 26 > 10, 24.

Therefore, [tex]\boxed{\bf\: 26 \: units }[/tex] is the hypotenuse  of the triangle with side lengths as 10, 26, 24 units.

[tex]\rule{150pt}{2pt}[/tex]

#1

Put it

[tex]\\ \rm\Rrightarrow p=100000(0.25)^{3}[/tex]

[tex]\\ \rm\Rrightarrow p=100000(0.015625)[/tex]

[tex]\\ \rm\Rrightarrow p=1562.5[/tex]

Now

#2

Let's see

[tex]\\ \rm\Rrightarrow 100000(0.25)^d=1000000[/tex]

[tex]\\ \rm\Rrightarrow 0.25^d=10[/tex]

[tex]\\ \rm\Rrightarrow ln0.25^d=ln10[/tex]

[tex]\\ \rm\Rrightarrow dln0.25=2.3[/tex]

[tex]\\ \rm\Rrightarrow d(-1.39)=2.3[/tex]

[tex]\\ \rm\Rrightarrow d=-1.654[/tex]

Answer:

92%

Step-by-step explanation:

To convert a fraction to a percent, you can divide the numerator by the denominator to end up with a decimal, in this case 0.92. Then, to convert to a percent, move the decimal two places to the left. As a result, we have 92%.

hope this helps!

Answer:

208 m²

Step-by-step explanation:

[tex]16 \: m\times 13 \: m = 208 \: {m}^{2} [/tex]

Answer:

The only right angles are between the lines (O,F) and (Q,D)

Step-by-step explanation:

by examination. The tangental line goes through the same point the diameter line goes through so to be tangental it has to be 90 degrees on each side.

Answer:

written out in the explanation.

Step-by-step explanation:

Area of a circle = [tex]\pi r^{2}[/tex]

Circumference of a circle = [tex]2\pi r[/tex]

The radius is the center point of a circle to the edge of a circle. The diameter is a line from one edge of a circle to the opposite edge.

So, the radius is simply half of the diameter.

For circle A, the radius is 12. Therefore, the diameter is 24.

The circumference is 2·[tex]\pi[/tex]·12 ≈ 75.39822 inches. rounded, the circumference is 75.4 inches.

The area is [tex]\pi 12^{2}[/tex] ≈ 452.38934. rounded, the area is 452.39.

For B,

you have already solved the diameter and radius correctly, good job :). The steps for finding the circumference are the same as for circle A.

the circumference is 2·[tex]\pi[/tex]·6 ≈ 37.69911. rounded, the circumference is 37.7 inches.

the area is [tex]\pi 6^{2}[/tex] ≈ 113.09734. rounded, the area is 113.1.

For C,

the circumference is 12. We can use the circumference equation to solve for the radius.

12 = [tex]2\pi r^{2}[/tex]

divide both by 2[tex]\pi[/tex]

7.63943726841 = [tex]r^{2}[/tex]

square root of 7.63943726841 = 2.76395319577

radius = 2.76395 inches. rounded, the radius is 2.8 inches.

so, radius ·2 = 5.52790639154.

meaning diameter = 5.52791. rounded, the diameter is 5.5 inches.

the area is [tex]\pi 2.76395^{2}[/tex] ≈23.99994. rounded, the area is 24.

Answer:

Low

Step-by-step explanation:

Low because it only overlaps twice.

Answer:

Negative

Step-by-step explanation:

This is the same as saying -12,365 + 110

This equals -12,265

Hope that helps!

Answer:

Same sign - Positive

Different sign - Negative

only for some maths

Answer:

y = -2 -3x

x = -2/3 -y/3

y =-3x -2

Slope=-6.000/2.000=-3.000

2*y+6*x-(-4)=0

2y + 6x + 4  =   2 • (y + 3x + 2)

Step-by-step explanation:

The bold letters are the important and answer :)

hoped this helped

if the answer is wrong tell me pls

Answer:

24 ft^2

Step-by-step explanation:

The srface area consisists of 2 triangles and 3 rectangles.

Surface area = 2 * 1/2 *4 * 3 + 1*4 + 1*5 + 1*3

= 12 + 4 + 5 + 3

=  24 ft^2.

Answer:

y = 3x - 2

Step-by-step explanation:

If two lines are parallel to each other, they have the same slope slopes.

The first line is y = 3x + 7. Its slope is 3. A line parallel to this one will also have a slope of 3.

Plug this value (3) into your standard point-slope equation of y = mx + b.

y = 3x + b

To find b, we want to plug in a value that we know is on this line: in this case, it is (-4, -14). Plug in the x and y values into the x and y of the standard equation.

-14 = 3(-4) + b

To find b, multiply the slope and the input of x (-4)

-14 = -12 + b

Now, add 12 to both sides to isolate b.

-2 = b

Plug this into your standard equation.

y = 3x - 2

This equation is parallel to your given equation (y = 3x + 7) and contains point (-4, -14)

Hope this helps!

Learn with another example:

https://brainly.com/question/27121082

Answer:

4(2x) - 8x + 4

4 × 2x = 8x

8x - 8x + 4

= 4

Done!

Answer:

78000000

Step-by-step explanation:

(7.8 x 10^3) (1.0 x 10^4) =?

Answer:

Area = 202 in^2

Step-by-step explanation:

Divide those into pieces to solve for each area and then add the area together.

Left Rectangle:

13 in * 4 in = 52 in^2

Right Rectangle:

15 in * 10 in = 150 in^2

Total Area = 117 in^2 + 150 in^2 = 202 in^2