If the ratio of blue shirts to white shirts is 5:3 If there were 21 white shirts how many blue shirts are there

A website offers free shipping to customers who order at least $75 dollars worth of merchandise. Della is ordering 2 flashlights

Vlada [557]

It’s A. 11 or more
YW

6 0

3 years ago

Read 2 more answers

Expand the following 3(x+9)

mina [271]

Answer: I'm pretty sure its 3x+27

Step-by-step explanation: So all you have to do is multiply everything in the parentheses by 3. So you would do 3 times x and it would be 3x and then 3 times 9 which will get you 27. After you just put it back into a equation 3x+27

5 0

2 years ago

What is the equation of the best-fitting regression line? Find this in two ways. First, using the regression analysis part of th

Lemur [1.5K]

Step-by-step explanation:

Regression analysis is used to infer about the relationship between two or more variables.

The line of best fit is a straight line representing the regression equation on a scatter plot. The may pass through either some point or all points or none of the points.

Method 1:

Using regression analysis the line of best fit is: $y=\alpha +\beta x+e$

Here α = intercept, β = slope and e = error.

The formula to compute the intercept is:

$\alpha =\bar y-\beta \bar x$

Here $\bar y$ and $\bar x$ are mean of the y and x values respectively.

$\bar y=\frac{\sum y_{i}}{n} \\\bar x=\frac{\sum x_{i}}{n}$

The formula to compute the slope is:

$\beta =\frac{\sum (x-\bar x)(y - \bar y)}{\sum (x=\bar x)^{2}}$

And the formula to compute the error is:

$e=y-\alpha -\beta x$

Method 2:

The regression line can be determined using the descriptive statistics mean, standard deviation and correlation.

The equation of the line of best fit is:

$(y-\bar y)=r\frac{\sigma_{x}}{\sigma_{y}} (x-\bar x)$

Here r = correlation coefficient = $r=\frac{Cov (x,y)}{\sqrt{\sigma^{2}_{x}\sigma^{2}_{y}} }$

$\sigma_{x}$ and $\sigma_{y}$ are standard deviation of x and y respectively.

$\sigma_{x}=\frac{1}{n}\sum (x-\bar x)^{2} \\\sigma_{y}=\frac{1}{n}\sum (y-\bar y)^{2}$

3 0

3 years ago

Can someone help me with this work please

tangare [24]

Answer:

-See below

Step-by.step explanation:

In the first column, on the left of the vertical line, you place the first digit of the number , then on the second row on you place the second digit.

So on the second row you have the entries:

1 | 2 2 4 representing 12, 12 and 14.

On the first row the 2 0ne digit numbers 3 and 8 are represented by

0 | 3 8.

Similarly the last 2 rows are:

2 | 0 1 3 6

3 | 4

8 0

3 years ago

For how many real values of x is <img src="https://tex.z-dn.net/?f=%20%5Csqrt%7B120-%5Csqrt%7Bx%7D%7D%20" id="TexFormula1" title

leva [86]

A good place to start is to set $\sqrt{x}$ to y. That would mean we are looking for $\sqrt{120-y}$ to be an integer. Clearly, $y\leq 120$ , because if y were greater the part under the radical would be a negative, making the radical an imaginary number, not an integer. Also note that since $\sqrt{x}$ is a radical, it only outputs values from $[0,\infty]$ , which means y is on the closed interval: $[0,120]$ .

With that, we don't really have to consider y anymore, since we know the interval that $\sqrt{x}$ is on.

Now, we don't even have to find the x values. Note that only 11 perfect squares lie on the interval $[0,120]$ , which means there are at most 11 numbers that x can be which make the radical an integer. All of the perfect squares are easily constructed. We can say that if k is an arbitrary integer between 0 and 11 then:

$\sqrt{120-\sqrt{x}}=k \implies \\ \sqrt{x}=k^2-120 \implies\\ x=(k^2-120)^2$

Which is strictly positive so we know for sure that all 11 numbers on the closed interval will yield a valid x that makes the radical an integer.

5 0

3 years ago