Can someone please help me I tryed already

Which of these points are on a line that has a slope of -3?

Ira Lisetskai [31]

Simple....

using the formula $\frac{ y_{1}- y_{2} }{ x_{1}- x_{2} }$ to find slope....

1.) (9,2)(4,3)

$\frac{2-3}{9-4}= -\frac{1}{5}$ (No)

2.) (9,2)(3,4)

$\frac{2-4}{9-3} = -\frac{2}{6} =- \frac{1}{3}$ (No)

3.) (2,9)(3,4)

$\frac{9-4}{2-3} = \frac{5}{-1} =-5$ (No)

4.) (2,9)(4,3)

$\frac{9-3}{2-4} = \frac{6}{-2} =-3$ (YES!)

Thus, your answer.

3 0

3 years ago

Earth revolves on its axis once every 24 hours. Which statement are true ? Check all that apply

zhuklara [117]

Answer:

The angular velocity of Earth is π/12 radians per hour.

The angular velocity of Earth is 2π radians per day.

Step-by-step explanation:

A full circumference of a circle (as the Equator line on Earth) is 2π radians.

Since the planet does a full revolution in 24 hours... that means it makes a full turn in a day.

So, we can see that in a day, the planet rotates 360 degrees... or 2π radians per day!

Now, if you want to find the angular velocity per HOUR... you divide that by 24... so 2π/24 = π/12 radians

So, we can also say it does π/12 radians per hour.

3 0

2 years ago

The population standard deviation for the typing speeds for secretaries is 4 words per minute. If we want to be 90% confident th

Oksana_A [137]

Answer:

The minimum sample size that should be taken is 62.

Step-by-step explanation:

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1-0.9}{2} = 0.05$

Now, we have to find z in the Ztable as such z has a pvalue of $1-\alpha$ .

So it is z with a pvalue of $1-0.05 = 0.95$ , so $z = 1.645$

Now, find the margin of error M as such

$M = z*\frac{\sigma}{\sqrt{n}}$

In which $\sigma$ is the standard deviation of the population and n is the size of the sample.

If we want to be 90% confident that the sample mean is within 1 word per minute of the true population mean, what is the minimum sample size that should be taken

This is n when $M = 1, \sigma = 4$ . So