1. 9=8+3a-8

VMariaS [17]

The variance method is as follows.

-Sum the squares of the values in data set, and then divide by the number of values in data set
- From that, subtract the square of the mean (add all values and divide by number of values in the data set)

Our variance is

 $\displaystyle\sigma^2 = \frac{2^2 + 5^2 + m^2}{3} - \left(\frac{2 + 5 + m}{3}\right)^2$

Since variance has to be 14, we set $\sigma^2 = 14$ and solve for m

$14= \frac{4 + 25 + m^2}{3} - \left(\frac{7 + m}{3}\right)^2\ \Rightarrow \\ \\
14 = \frac{29}{3} + \frac{1}{3}m^2 - \frac{1}{9}(7+m)^2 \\ \\
14 = \frac{29}{3}+ \frac{1}{3}m^2 - \frac{1}{9}(49 + 14m + m^2) \\ \\
14 = \frac{29}{3}+ \frac{1}{3}m^2 - \frac{49}{9}- \frac{14}{9}m- \frac{1}{9}m^2 \\ \\
0 = \frac{-88}{9} -\frac{14}{9}m + \frac{2}{9}m^2
$

quadratic formula

$m = \displaystyle\frac{-b \pm \sqrt{b^2 -4ac}}{2a} \\
m = \frac{-(-\frac{14}{9}) \pm \sqrt{\left(-\frac{14}{9}\right)^2 - 4(2/9)(-88/9)} }{2(2/9)} \\
m = \frac{\frac{14}{9} \pm \sqrt{ \frac{196}{81} + \frac{704}{81} } }{\frac{4}{9} } \\
m = \frac{\frac{14}{9} \pm \sqrt{ \frac{900}{81} } }{\frac{4}{9} } \\
m = \frac{\frac{14}{9} \pm \sqrt{ \frac{100}{9} } }{\frac{4}{9} } \\
m = \frac{\frac{14}{9} \pm \frac{10}{3} }{\frac{4}{9} } \\
m = 11, -4$

-4 doesnt' work as it is not a positive integer

m = 11

5 0

2 years ago

Please help with question 2, I’m too tired to think right now, and it’s for my little sister and it’s due tomorrow! Ignore the n

marishachu [46]

Answer:

2000 L

Step-by-step explanation:

There are 1250 L of water in a tank at present. If the tank is 0.625 full, what is the capacity of the tank?

The simple solution is:

1250 L ÷ 0.625 = 2000 L

The algebraic solution is:

Let c equal the capacity of the tank.

Therefore, c × 0.625 = 1250.

Divide both sides by 0.625:

c × 0.625 ÷ 0.625 = 1250 ÷ 0.625

And simplify:

c = 1250 ÷ 0.625

c = 2000

5 0

2 years ago

What is the pattern 3.5 to 13

mars1129 [50]

Adding 9.5 every time

4 0

2 years ago

Can you help me please here is the image

erica [24]

Answer:

f=u+2

Step-by-step explanation:

math

7 0

2 years ago

PLEASE HELPPP!!!! Will give brainiest!!!!

Lady_Fox [76]

Answer:

0.008 °C

Explanation:

1) Write the changes in the temperature of the city over the 4 days in an easy way to read.

1.34 °C

- 5 / 7 °C

- 0.75 °C

4/9 ° C

2) Write the expression to show the average daily change in temperature.

The average of a set of data is calculated with the expression:

Average = (sum of the data) / amount of data

Hence, you need to add the four change of temperature data and divide by 4.

The expression is:

Average = [ 1.34 °C + (- 5 / 7 °C) + ( - 0.75 °C) + 4/9 ° C ] / 4

3) Write the steps to solve the expression:

You can choose between adding fractions or adding the decimal forms of the numbers.

If you choose adding decimals, keep the complete decimals in your calculator, to avoid the accumulation of errors due to rounding. Round only the final result.

These are the steps.

a. Find the decimal forms of the fractions:

- 5/7 ≈ 0.71428

4 /9 ≈ 0.44444

b. Add the four data:

1.34°C + (- 0.71428 °C) + (-0.75 °C) + 0.44444 °C ≈ 0.32019 °C

c. Divide the sum by the number of data (4)

0.32019 °C / 4 ≈ 0.080004 °C

4. Round to the nearest hundredth

The place of the hundreth is the second after the decimal point, which is 8 in this case:

0.080004 °C ≈ 0.08 °C

7 0

2 years ago