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3 years ago

Can someone help with question 3

Mathematics

1 answer:

kirza4 [7]3 years ago

4 0

Answer:

This is what you have to explain:

With 5n, you are multiplying a number and a variable.

With 5 + n, you are adding a number and a variable.

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The sum of two numbers is 20. Their difference is 14. Find the numbers.

Mila [183]

3 and 17
17-3=14

hope that helps

5 0

4 years ago

Read 2 more answers

Help plz 6(2x - 11) + 15 = 3x + 12

Ket [755]

Answer:

x = 7

Step-by-step explanation:

Lets do the brackets first,

6 × 2x = 12

6 × -11 = -66

------

Calculate the x constant:

12x - 3x = 9x

-------

Then the ones with no x:

-66 + 15 = -51

51 + 12 = 63

-------

Lastly, divide

63 ÷ 9 = 7

-------

Have a good day :)

3 0

3 years ago

Read 2 more answers

Can you step by step solve 20x+12=4x-16

Murljashka [212]

Answer:

x = - $\frac{7}{4}$

Step-by-step explanation:

Given

20x + 12 = 4x - 16 ( subtract 4x from both sides )

16x + 12 = - 16 ( subtract 12 from both sides )

16x = - 28 ( divide both sides by 16 )

x = $\frac{-28}{16}$ = - $\frac{7}{4}$ [ = - 1.75 ]

4 0

4 years ago

2. In your own words, explain HOW to find the standard deviation of this data set. (20 points) 3. What does the standard deviati

Ket [755]

Answer:

$\sigma = 11.28$ --- Standard deviation

Step-by-step explanation:

Given

See attachment for graph

Solving (a): Explain how the standard deviation is calculated.

Start by calculating the mean

To do this, we divide the sum of the products of grade and number of students by the total number of students;

i.e.

$\bar x = \frac{\sum fx}{\sum f}$

So, we have:

$\bar x = \frac{50 * 1 + 57 * 2 + 60 * 4 + 65 * 3 +72 *3 + 75 * 12 + 77 * 10 + 81 * 6 + 83 * 6 + 88 * 9 + 90 * 12 + 92 * 12 +95 * 2 + 99 * 4 + 100 * 5}{1 + 2 + 4 + 3 +3 + 12 + 10 + 6 + 6 + 9 + 12 + 12 +2 + 4 + 5}$

$\bar x = \frac{7531}{91}$

$\bar x = 82.76$

Next, calculate the variance using the following formula:

$\sigma^2 = \frac{\sum f(x - \bar x)^2}{\sum f}$

i.e subtract the mean from each dataset; take the squares; add up the squares; then divide the sum by the number of dataset

So, we have:

$\sigma^2 = \frac{1 * (50 - 82.76)^2 +...................+ 5 * (100 - 82.76)^2}{91}$

$\sigma^2 = \frac{11580.6816}{91}$

$\sigma^2 = 127.26$

Lastly, take the square root of the variance to get the standard deviation

$\sigma = \sqrt{\sigma^2}$

$\sigma = \sqrt{127.26}$

$\sigma = 11.28$ --- approximated

Hence, the standard deviation is approximately 11.28

Considering the calculated mean (i.e. 82.76), the standard deviation (i.e. 11.28) is small and this means that the grade of the students are close to the average grade.

8 0

3 years ago

What is 1/4 as a multiplication sentence

Phoenix [80]

1/4 is the same as 1 * 0.25

3 0

3 years ago

Read 2 more answers