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vlabodo [156]
4 years ago
7

Prove that for any natural n the value of the expression (n+7)^2–n^2 is divisible by 7.

Mathematics
1 answer:
Afina-wow [57]4 years ago
3 0

Step-by-step explanation:

(n + 7)² – n²

n² + 14n + 49 – n²

14n + 49

7 (2n + 7)

7 is a factor, so for any natural n, (n + 7)² – n² is a multiple of 7.

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Help pls ????????!!!!!!
7nadin3 [17]

Answer:

let the number of steps taken by friend 1, 2 and 3 be: x, y and z respectively

we know that the mean of the total steps taken by all the friends is 10,350

Since the formula for mean is: sum of all values / number of values

here, the total values is the total number of steps taken

So,

steps taken by friend 1  +steps taken by friend 2 +steps taken by friend 3 +steps taken by friend 4 +steps taken by friend 5 +steps taken by friend 6

all that divided by 6 will give us the mean

so,  <em>7800 + 8000 + 9800 + x + y + z / 6</em>

<em>(25600 + x + y + z)/6 = 10350</em>

<em>25600 + x + y + z = 10350 * 6</em>

<em>x + y + z = 62100 - 25600</em>

x + y + z = 36500

So since the sum of x, y and z is 36500,

we can say that the average value of x , y and z is 12167 (36500/3)

So the next thing to make an equation out of is Median

to find the median, we need to arrange the values in any order you like, i will arrange in descending order

so since the estimated value of all x , y and z is greater than the greatest known value:

x > y > z > 9800 > 8000 > 7800

Since this set of values has an even number of values, we will take the average of the middle 2 values as the median

<em>(9800 + z)/2 = 10000</em>

<em>9800 + z = 20000</em>

z = 10200 -------- we have found one of the three values! getting closer

Now, the final equation will be found from the range

since we already have sorted our data, and the difference of the highest and lowest is the range

x > y > z > 9800 > 8000 > 7800

So, x - 7800  = 7500

x = 15300 ------- now that we have x and z, we can use the first equation to find the value of y and we will be done!

<em>x + y + z = 36500</em>

<em>replacing the values</em>

<em>15300 + y + 10200 = 62100</em>

<em>y = 36500 - 25500</em>

<em>y = 11000</em>

So the three remaining friends walked

15300, 11000 and 10200 steps

6 0
3 years ago
5x+17=-8 solve the equation
kirill115 [55]

5x=-8-17

5x=-25

x=-25/5

x=-5

7 0
3 years ago
A real world solution for <br> 4.5n+2.5=19
brilliants [131]

Answer:

n = 3.666 or (3 and 2/3)

Step-by-step explanation:

4.5n + 2.5 = 19

4.5n = 19 - 2.5

4.5n = 16.5

n = 16.5 / 4.5

n = 3.666 or (3 and 2/3)

3 0
3 years ago
Question 6 of 40
chubhunter [2.5K]

Step-by-step explanation:

I cannot really identify and read the provided answer options.

the solution to the sequence 2, 6, 10, 14, 18, ... is

an = 4×(n-1) + 2

recursive that is

a1 = 2

an = an-1 + 4

please pick the right option in your original problem definition that fits to this solution.

5 0
3 years ago
El padre de Teresa tiene que poner un cristal hexagonal en la mesa del comedor. Si el lado mide 50 cm y la apotema mide mide 40
N76 [4]

Answer:

the area of the glass is 1000cm^2

Step-by-step explanation:

Given that

The side is 50 cm

And, the power is 40 cm

We need to find out the area of the glass

So, the area of the glass is

= (50 × 40 ) ÷ 2

= 2,000 ÷ 2

= 1,000 cm^2

Hence, the area of the glass is 1000cm^2

The same is to be considered and relevant

8 0
3 years ago
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