Students in a large statistics class were randomly divided into two groups. The first group had a midterm exam that was printed on canary paper while the second group had the exam printed on pale green paper. The exam scores of the two groups were then then compared.This experiment was not blind because:_______a. Students were allowed to keep their eyes open while taking the exam.b. The exam was too long.c. The students knew whether or not music was playing while they were taking the exam.d. Some of the students did not study for the exam.e. Students were randomized into the two groups.

Answer:

The between the given vector and the positive direction of the x-axis is approximately 41.186º.

Step-by-step explanation:

Let be [tex]\vec u = 8\,i + 7\,j[/tex] and [tex]\vec v = i[/tex] (Positive direction of the x-axis), the angle between both vectors can be determined from definition of dot product:

[tex]\vec u \bullet \vec v = \|\vec u\|\cdot \|\vec v\| \cdot \cos \theta[/tex]

Angle is cleared:

[tex]\cos \theta = \frac{\vec u\bullet \vec v}{\|\vec u\|\cdot \|\vec v\|}[/tex]

[tex]\theta = \cos^{-1}\left(\frac{\vec u \bullet \vec v}{\|\vec u\|\cdot \|\vec v\|} \right)[/tex]

The norms of [tex]\vec u[/tex] and [tex]\vec v[/tex] are found by Pythagorean Theorem:

[tex]\|\vec u\| = \sqrt{8^{2}+7^{2}}[/tex]

[tex]\|\vec u\| \approx \sqrt{113}[/tex]

[tex]\|\vec v\| = 1[/tex]

The dot product between both vectors is:

[tex]\vec u \bullet \vec v = (8)\cdot (1) + (6)\cdot (0)[/tex]

[tex]\vec u \bullet \vec v = 8[/tex]

The angle is now calculated:

[tex]\theta = \cos^{-1}\left(\frac{8}{\sqrt{113}} \right)[/tex]

[tex]\theta \approx 41.186^{\circ}[/tex]

The between the given vector and the positive direction of the x-axis is approximately 41.186º.

Answer: the answer should be A

if this helps the equation format is y= mx + b your replace the with the slop and the b with the y intercept

the way to find the slope is rise over run

Step-by-step explanation:

Answer:

Following are the solution:

Step-by-step explanation:

Given equation:

[tex]\frac{dx}{dy}= \frac{y(y-2)}{2}........(a)[/tex]

[tex]\Phi (x) = \frac{2}{1-ce^x}[/tex]

In the question [tex]\Phi (x)[/tex], is a solution of the equation (a) only if when [tex]\Phi (x)[/tex]satisfies equation (a):

let us find [tex]\Phi' (x)[/tex]:-

[tex]\Phi(x) =\frac{d}{dx} \Phi (x)=\frac{d}{dx}(\frac{2}{1-ce^x})[/tex]

                        [tex]= 2 \frac{d}{dx}({1-ce^x}^-1)\\\\= 2 (-1) ({1-ce^x})^{-2} \frac{d}{dx}({1-ce^x})\\\\= -2 ({1-ce^x})^{-2} (-ce^x})\\\\= 2(-ce^x) ({1-ce^x})^{-2} \\\\[/tex]

Now:

[tex]\frac{dy}{dx}=\frac{y(y-2)}{2}\\\\\frac{d}{dx}\Phi (x) =\frac{\Phi (x) (\Phi (x)-2)}{2}\\[/tex]

by subtracting the value of [tex]\Phi (x)[/tex]and [tex]\frac{d}{dx}[/tex][tex]\Phi (x)[/tex],we get:

[tex]\to[/tex][tex]2ce^x(1-ce^x)^-2= \frac{(\frac{2}{1-ce^x})(\frac{2}{1-ce^x})^{-2}}{2}[/tex]

[tex]=2ce^x (1-ce^x)^{-2}=\frac{1}{2}[\frac{2}{1-ce^x}(\frac{2-2(1-ce^x)}{1-ce^x)}]\\\\= \frac{1}{1-ce^x} \times \frac{2ce^x}{1-ce^x}\\\\=\frac{2ce^x}{(1-ce^x)^2}\\\\=2ce^x (1-ce^x)^-2[/tex]

[tex]\bold{2ce^x(1-ce^x)^-2=2ce^x(1-ce^x)^-2}[/tex]

[tex]\Phi (x)[/tex] the solution of the given equation. [tex]\Phi (x)[/tex] has one Parameter Family of

[tex]\frac{dy}{dx}=\frac{y(y-2)}{2}[/tex]

[tex]\Phi (x) =\frac{2}{1-ce^x}\\\\_{when} \ \ \ c= 0 \to \Phi (x) =\frac{2}{1-0\times e^x}=2\\\\_{when} \ \ \ c= 1 \to \Phi (x) =\frac{2}{1-1\times e^x}=\frac{2}{1-e^x}\\\\_{when} \ \ \ c= -1 \to \Phi (x) =\frac{2}{1-(-1)\times e^x}=\frac{2}{1+e^x}\\\\_{when} \ \ \ c= 2 \to \Phi (x) =\frac{2}{1-(-2)\times e^x}=\frac{2}{1-2e^x}\\\\_{when} \ \ \ c= -2 \to \Phi (x) =\frac{2}{1-(-2)\times e^x}=\frac{2}{1+2e^x}\\\\[/tex]

5. Tania earns $13.50 per hour at the Glendale Florist. She regularly works 40 hours per week. She is paid time-and-a-half for each hour of overtime work. Last week she worked. 43 hours. What was her gross pay for the ...

Missing: michael ‎| Must include: michael

Answer:

- Decreasing  

Step-by-step explanation:

im not sure of the last two but the others are for sure a no

Answer:

1 : 20 20 students for every 1 teacher

Step-by-step explanation:

divide both sides by 12

Step-by-step explanation:

The second graph is the right one

Answer:

see below

Step-by-step explanation:

f(x) = -x-7 is of the form

y = mx+b  where m is the slope and b is the y intercept

The line  has a y intercept of (0,-7) and a slope of -1

A slope of -1 means the line goes down from left to right ( down 1 and to the right 1)

Answer:

No

Step-by-step explanation:

t the two equations for the lines into slope-intercept form. ...

Set the two equations for y equal to each other.

Solve for x. ...

Use this x-coordinate and plug it into either of the original equations for the lines and solve for y.

If 2x+7>=0, x>=-3.5 then |2x+7|=2x+7.

Then the inequality becomes:

2x+7>23, 2x>16, x>8.(which is an acceptable result since we already assumed x>=-3.5)

If 2x+7<0, x<-3.5 then |2x+7|= -(2x+7).

Then the inequality becomes:

-(2x+7)>23, 2x+7<-23, 2x <-30, x<-15.

(which is an acceptable result since we already assumed x<-3.5)

Thus the answer is x<-15 or x>8.

The graph is simple. You draw the line of real numbers and "shadow" all numbers above 8 and all numbers bellow - 15.

Answer:

[tex]\huge\boxed{\sf x = 14 , y = 10}[/tex]

Step-by-step explanation:

Let the two numbers be x and y

Condition # 1:

Condition # 2:

[tex]\rule[225]{225}{2}[/tex]

Putting Equation # 2 in Equation # 1

2y - 6 + y = 24

3y - 6 = 24

Adding 6 to both sides

3y = 24 + 6

3y = 30

Dividing both sides by 3

y = 10

[tex]\rule[225]{225}{2}[/tex]

Putting y = 10 in Equation # 2

x = 2y - 6

x = 2(10) - 6

x = 20 - 6

x = 14

[tex]\rule[225]{225}{2}[/tex]

The two numbers are 10 and 14.

The sum of 2 numbers is 24.

let the number be x and y . Therefore,

x + y = 24

One is 6 less than twice the other. therefore,

2x - y = 6

Combine the equations

x + y = 24

2x - y = 6

3x = 30

x = 30 / 3

x = 10

x + y = 24

10 + y = 24

y = 24 - 10

y = 14

The 2 numbers are 10 and 14 .

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Answer:

0

Step-by-step explanation:

-115-(-115)

Subtracting a negative is like adding

-115 + 115

0

The answer is 0

Because they subtract each other

Answer:

No

Step-by-step explanation:

Its 1000

Answer:

perfect square

Step-by-step explanation:

Answer:

Step-by-step explanation:

Given the 2 by 2 matrix [tex]A = \left[\begin{array}{-cc}x&5\\y&-8\\\end{array}\right][/tex] , we are to find the value of x and y for the expression A² = A to be true.

First we need to find A² by multiplying the same matrix together

[tex]A^2 = \left[\begin{array}{-cc}x&5\\y&-8\\\end{array}\right] \left[\begin{array}{-cc}x&5\\y&-8\\\end{array}\right]\\\\ \ we \ normally \ multiply \ the \ rows \ of \ the \ first \ matrix \ with \ the \ column \ of \ the \ second \\\\A^2 = \left[\begin{array}{-cc}x^2+5y&5x-40\\xy-8y&5y+64\\\end{array}\right]\\\\Since \ A^2 = A,\ hence;\\\\\left[\begin{array}{-cc}x^2+5y&5x-40\\xy-8y&5y+64\\\end{array}\right] = \left[\begin{array}{-cc}x&5\\y&-8\\\end{array}\right]\\[/tex]

Equating the first row and second column of both matrices together, we will have;

5x-40 = 5

add 40 to both sides of the equation

5x-40+40 = 5+40

5x = 45

x = 45/5

x = 9

Similarly,  we will equate the second row and second column of both matrices to have;

5y+64 = -8

Subtract 64 from both sdies

5y+64-64 = -8-64

5y = -72

y = -72/5

Hence the value of x is 9 and y is -72/5

Matrices are used to represent data in rows and columns

The values of x and y are 9 and -14.4 respectively.

Matrix A is represented as:

[tex]\mathbf{A = \left[\begin{array}{ccc}x&5\\y&-8\end{array}\right] }[/tex]

Calculate [tex]\mathbf{A^2}[/tex]

[tex]\mathbf{A^2 = \left[\begin{array}{ccc}x&5\\y&-8\end{array}\right] \times \left[\begin{array}{ccc}x&5\\y&-8\end{array}\right] }[/tex]

Recall that [tex]\mathbf{A^2 = A}[/tex]

This means that:

[tex]\mathbf{\left[\begin{array}{ccc}x^2++5y&5x-40\\xy-8y&5y+64\end{array}\right] = \left[\begin{array}{ccc}x&5\\y&-8\end{array}\right] }[/tex]

So, by comparison

[tex]\mathbf{5x - 40 = 5}[/tex]

[tex]\mathbf{5x = 40 + 5}[/tex]

[tex]\mathbf{5x = 45}[/tex]

[tex]\mathbf{x = 9}[/tex]

Similarly

[tex]\mathbf{5y + 64 = -8}[/tex]

[tex]\mathbf{5y =-64 -8}[/tex]

[tex]\mathbf{5y =-72}[/tex]

[tex]\mathbf{y =-14.4}[/tex]

Hence, the values of x and y are 9 and -14.4 respectively.

Read more about matrices at:

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Answer:

15.6 is the right answer

Step-by-step explanation:

Answer: B.  |x-100| = 25

Explanation:

Draw out a number line. Mark 75, 100 and 125 on the number line as points A, B, and C in that order. Don't worry about the spacing.

The value of x represents where the train is. So if we had say x = 85, then it would be at location 85 on the number line. Writing |x-100| is the distance from x to 100. The absolute value ensures the distance is never negative. We want this distance to be 25 because after traveling 25 cm, the switch is turned, and the train goes the other way.

The equation which models the movement of the train is represented by |x − 100| = 25. The correct option is B.

One-variable linear equation The equation for a linear equation in one variable is written as ax+b = 0, where a and b are two integers, and x is a variable. This equation has only one solution. For instance, the linear equation 2x+3=8 only has one variable.

The train's location is indicated by the value of x. Therefore, if x were to equal, let's say, 85, it would be at position 85 on the number line.

The distance between x and 100 is expressed as |x-100|. The distance will never be negative thanks to the absolute value. Because the switch is switched after the train has traveled 25 cm in one direction, we need this distance to be 25 cm.

Therefore, the equation which models the movement of the train is represented by |x − 100| = 25. The correct option is B.

To know more about an equation follow

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Answer:

y = -7

Step-by-step explanation:

3(-4) = y - 5

-12 = y - 5

y = -12 + 5

y = -7

Answer:

its an integer

Step-by-step explanation:

Because it has a negative sign

Answer:

ffdfssss

Step-by-step explanation:

fdfdfdfd

Answer:

x is invalid.

Step-by-step explanation:

Note the equal sign, what you do to one side, you do to the other. Remember to follow PEMDAS.

PEMDAS is the order of operation, and =

Parenthesis

Exponents (& Roots)

Multiplication

Division

Addition

Subtraction

First, distribute -4 to all terms within the parenthesis:

-4(1 - 6x) = (-4 * 1) + (-4 * -6x) = -4 + 24x

24x - 22 = -4 + 24x

Isolate the variable, x. Subtract 24x from both sides:

24x (-24x) - 22 = -4 + 24x (-24x)

0 - 22 = -4 + 0

-22 ≠ -4, therefore, this question is invalid.

~

Answer:

3 + 9i

Step-by-step explanation:

(4 + 2i) - (1 - 7i)

distribute the (-)

(4 + 2i) - 1 + 7i

combine like terms

3 + 9i

Answer:

C

Step-by-step explanation:

24÷6= 6 Hope this helps.

Answer:

Height = 1 inch

Step-by-step explanation:

area of triangle = 1/2 x base x height

       11.5 =1/2 x 23 x height

       23/23 = height

       height = 1

h = 1 inches

The area of a triangle = formula

A = b×h/2

2A = b×h

h = 2A/b

h = 2×11.5in²/23in

= 23in²/23in

= 1 in

Answer:

50%

Step-by-step explanation:

34+16=50% he or she ate half of the pizza

Answer:

Step-by-step explanation:

2+3+4+5+6=20

20/20=4,000,000

2/20=?

2/20×4,000,000÷20/20=400,000

20/20=4,000,00

3/20

3/20×4000000÷20/20=600,000

20/20=4,000,000

4/20

4/20×4,000,000÷20/20=800,000

20/20=4,000,000

5/20

5/20×4,000,000÷20/20=1,000,000

20/20=4,000,000

6/20

6/20×4,000,000÷20/20= 1,200,000

2:3:4:5:6=400,000 :600,000: 800,000 : 1,000,000: 1,200,000

Answer:

X=2

Step-by-step explanation:

|2x -12| = -4x

2x-12 = -4x

2x - (-4x) = 12

2x +4x =6x

6x=12

x=12/6

x=2

Answer:

8

Step-by-step explanation:

8 is the digit after 7  and previous to 9