All categories

3 years ago

A.a + b.b = 612 And a+b = 30 so a.b? Pls help.

Mathematics

1 answer:

yawa3891 [41]3 years ago

4 0

Answer:

ab = 144

Step-by-step explanation:

Assuming you mean a² + b² = 612, then

(a + b)² = a² + 2ab + b² , that is

30² = a² + 2ab + b² , so

a² + 2ab + b² = 900

a² + b² + 2ab = 900 ← substitute a² + b² = 612

612 + 2ab = 900 ( subtract 612 from both sides )

2ab = 288 ( divide both sides by 2 )

ab = 144

You might be interested in

Examine the following table, which represents some points on a line

Lady bird [3.3K]

Answer:

Option (b)

Step-by-step explanation:

Let the points represented by the given table lie on a line.

And the equation of the line is,

y = mx + b

Where m = slope of the line

b = y-intercept

Let the points lying on the line are (0, -2) and (3, -3)

Slope of the line 'm' = $\frac{y_{2}-y_{1}}{x_{2}-x_{1}}$

m = $\frac{-2-(-3)}{0-3}$

m = $\frac{-2+3}{0-3}$

m = - $\frac{1}{3}$

y-intercept 'b' = (-2)

Equation of the line is,

y = $-\frac{1}{3}x-2$

This equation matches with equation given in option (b).

Option (b) will be the answer.

7 0

4 years ago

After the financial crisis that hits the country of Barbaria in 2012, a total of 9 million people are unemployed. If 35 million

tatuchka [14]

Answer:

$25.71\%$

Step-by-step explanation:

The Unemployment rate of a country is calculated as a fraction of its Labor force. In Barbaria,

Number of Unemployed =9 million

Number of Employed =35 Million

Labor Force = (9+35) Million =44 Million

$Unemployment Rate=\frac{\text{Unemployed People}}{\text{Labour force}} X 100\\=\frac{9}{35}X100\\ =25.71\%$

The Unemployment rate in Barbaria in 2012 was 25.71%.

8 0

3 years ago

Each side of the regular hexagon below measures 8 cm. What is the area of the hexagon?

sineoko [7]

A regular hexagon can be split into 6 congruent equilateral triangles.
the area of an equilateral triangle is √3*s²/4, where s is the side length
Area of the hexagon
= 6*√3*8²/4
= 96√3 square centimeters

6 0

3 years ago

Read 2 more answers

What is the ratio of 178?

prisoha [69]

The factors of 178178 are all numbers between -178178 and 178178 that divide 178178 evenly.−178,−89,−2,−1,1,2,89,178-178,-89,-2,-1,1,2,89,178

3 0

3 years ago

A random sample of 21 observations is used to estimate the population mean. The sample mean and the sample standard deviation ar

stepladder [879]

Answer:

a. CI=[128.79,146.41]

b. CI=[122.81,152.39]

c. As the confidence level increases, the interval becomes wider.

Step-by-step explanation:

a. -Given the sample mean is 137.6 and the standard deviation is 20.60.

-The confidence intervals can be constructed using the formula;

$\bar X\pm \ z\frac{s}{\sqrt{n}},$

where:

$s$ is the sample standard deviation
$z$ is the s value of the desired confidence interval

we then calculate our confidence interval as:

$\bar X\pm z\frac{s}{\sqrt{n}}\\\\=137.60\pm z_{0.05/2}\times\frac{20.60}{\sqrt{21}}\\\\=137.60\pm1.960\times \frac{20.60}{\sqrt{21}}\\\\=137.60\pm8.8108\\\\\\=[128.789,146.411]$

Hence, the 95% confidence interval is between 128.79 and 146.41

b. -Given the sample mean is 137.6 and the standard deviation is 20.60.

-The confidence intervals can be constructed using the formula in a above;

$\bar X\pm z\frac{s}{\sqrt{n}}\\\\=137.60\pm z_{0.01/2}\times\frac{20.60}{\sqrt{21}}\\\\=137.60\pm3.291\times \frac{20.60}{\sqrt{21}}\\\\=137.60\pm 14.7940\\\\\\=[122.806,152.394]$

Hence, the variable's 99% confidence interval is between 122.81 and 152.39

c. -Increasing the confidence has an increasing effect on the margin of error.

-Since, the sample size is particularly small, a wider confidence interval is necessary to increase the margin of error.

-The 99% Confidence interval is the most appropriate to use in such a case.

7 0

4 years ago