Civil engineers often use the straight-line equation, y Bo +B1x, to model the relationship between the mean shear strength of masonry joints and precompression stress, x. To test this theory, a series of stress tests were performed on solid bricks arranged in triplets and joined with mortar. The precompression stress was varied for each triplet and the ultimate shear load just before failure (called the shear strength) was recorded. The stress results for n 7 triplet tests is shown in the accompanying table followed by a printout of the regression analysis. Give a practical interpretation of the estimate of the slope of the least squares line. Round to three decimal places if needed.
Click the icon to view the table of results and the regression analysis
A. or every 1 ton increase in precompression stress, the shear strength of the joint is estimated to increase by 0.987 tons.
B. For a triplet test with a precompression stress of o tons, the shear strength of the joint is estimated to be 1.192 tons.
C. For a triplet test with a precompression stress of 1 ton, the shear strength of the joint is estimated to be 0.987 tons.
D. For every 0.987 ton increase in precompression stress, the shear strength of the joint is estimated to increase by 1 ton.

Answer:

2±√13

Step-by-step explanation:

9/x=x-4

x² -4x - 9=0

x² -4x +4- 13=0

(x -2)²=13

x-2= ±√13

x= 2±√13

Answer: 28

Step-by-step explanation: Im taking the same class here is a photo of the work, divide 56/2 than you get 28

Answer:

The area of the triangle is 18.70 sq.units.

Step-by-step explanation:

It is provided that a triangle is bounded by the y-axis, the line [tex]f(x)=y=9-\frac{2}{3}x[/tex].

The slope of the line is: [tex]m_{1}=-\frac{2}{3}[/tex]

A perpendicular line passes through the origin to the line f (x).

The slope of this perpendicular line is:[tex]m_{2}=-\frac{1}{m_{1}}=\frac{3}{2}[/tex]

The equation of perpendicular line passing through origin is:

[tex]y=\frac{3}{2}x[/tex]

Compute the intersecting point between the lines as follows:

[tex]y=9-\frac{2}{3}x\\\\\frac{3}{2}x=9-\frac{2}{3}x\\\\\frac{3}{2}x+\frac{2}{3}x=9\\\\\frac{13}{6}x=9\\\\x=\frac{54}{13}[/tex]

The value of y is:

[tex]y=\frac{3}{2}x=\frac{3}{2}\times\frac{54}{13}=\frac{81}{13}[/tex]

The intersecting point is [tex](\frac{54}{13},\ \frac{81}{13})[/tex].

The y-intercept of the line f (x) is, 9, i.e. the point is (0, 9).

So, the triangle is  bounded by the points:

(0, 0), (0, 9) and [tex](\frac{54}{13},\ \frac{81}{13})[/tex]

Consider the diagram attached.

Compute the area of the triangle as follows:

[tex]\text{Area}=\frac{1}{2}\times 9\times \frac{54}{13}=18.69231\approx 18.70[/tex]

Thus, the area of the triangle is 18.70 sq.units.

Answer:

[tex]n = - 3[/tex]

Second answer is correct

Step-by-step explanation:

[tex]11(n - 1) + 35 = 3n \\ 11n - 11 + 35 = 3n \\ 11n - 3n = 11 - 35 \\ 8n = - 24 \\ \frac{8n}{8} = \frac{ - 24}{8} \\ n = - 3[/tex]

hope this helps

brainliest appreciated

good luck! have a nice day!

Answer:

40°

Step-by-step explanation:

2x = 3x - 20 add like terms

x = 20 and angle l is equal to 3x minus 20 so 3 × 20 - 20 = 40°

Answer:

63

Step-by-step explanation:

So just find the area of the carpet:

9 * 7 = 63

Answer:

1. (y - x)²  = 256

2. 128g needed to be added

Step-by-step explanation:

1.

9 + 5 + 2 + y + x = 2(8 + 4 + 1 + 3 + x)

16 + y + x = 32 + 2x

y - x = 16

∴ (y - x)²  = 256

2.

x = mass of alcohol to add

480 × 0.24 = 115.2 ← current mass of alcohol

0.4(480 + x) = 115.2 + x      (×5)

2(480 + x) = 576 + 5x

960 + 2x = 576 + 5x

3x = 384

x = 128g

Here is the full question .

We are interested in finding an estimator for [tex]Var (X_i )[/tex] and propose to use :

[tex]\hat {V} = \bar {X}_n (1- \bar {X} )_n[/tex]

Now; we are interested in the basis of [tex]\hat V[/tex]

Compute :

[tex]E \ \ [ \bar V] - Var (X_i) =[/tex]

Using this; find an unbiased estimator [tex][ \bar V][/tex] for [tex]p(1-p) \ if \ n \geq 2[/tex]

Write [tex]bar \ x{_n} \ for \ X_n[/tex]

Answer:

Step-by-step explanation:

[tex]\bar X_n = \dfrac{1}{n} {\sum ^n _ {i=1} } \\ \\ E(X_i) = - \dfrac{1}{n=1} \sum p \dfrac{1}{n}*np = \mathbf{p}[/tex]

[tex]V(\bar X_n) = V ( \dfrac{1}{n_{i=1} } \sum ^n \ X_i )} = \dfrac{1}{n^2} \sum ^n_{i=1} Var (X_i) \\ \\ = \dfrac{1}{n^2} \ \sum ^n _{i=1} p(1-p) \\ \\ = \dfrac{1}{n^2}*np(1-p) \\ \\ = \dfrac{p(1-p)}{n}[/tex]

[tex]E( \bar X^2 _ n) = Var (\bar X_n) + [E(\bar X_n)]^2 \\ \\ = \dfrac{p(1-p)}{n}+ p \\ \\ = p^2 + \dfrac{p(1-p)}{n} \\ \\ \\ \hat V = \bar X_n (1- \bar X_n ) = \bar X_n - \bar X_n ^2 \\ \\ E [ \hat V] = E [ \bar X_n - \bar X_n^2] \\ \\ = E[\bar X_n ] - E [\bar X^2_n] \\ \\ = p-(p^2 + \dfrac{p(1-p)}{n}) \\ \\ = p-p^2 -\dfrac{p(1-p)}{n}[/tex]

[tex]=p(1-p)[1-\dfrac{1}{n}] = p(1-p)\dfrac{n-1}{n}[/tex]

[tex]Bias \ (\bar V ) = E ( \hat V) - Var (X_i) \\ \\ = p(1-p) [1-\dfrac{1}{n}] - p(1-p) \\ \\ - \dfrac{p(1-p)}{n}[/tex]

Thus; we have:

[tex]E [\hat V] = p(1-p ) \dfrac{n-1}{n}[/tex]

[tex]E [\dfrac{n}{n-1} \ \ \bar V] = p(1 -p)[/tex]

[tex]E [\dfrac{n}{n-1} \ \ \bar X_n (1- \bar X_n )] = p (1-p)[/tex]

Therefore;

[tex]\hat V ' = \dfrac{n}{n-1} \bar X_n (1- \bar X_n)[/tex]

[tex]\mathbf{ \hat V ' = \dfrac{n \bar X_n (1- \bar X_n)} {n-1}}[/tex]

Answer:

I made is clear for you, now you may match each one

Step-by-step explanation:

f(1)= 11, f(n)= 3*f(n-1)

⊕ middle

f(1)= -18, f(n)= f(n-1)+21

f(1)= -18, f(n)= f(n-1) + 22

f(1)= -18, f(n)= 2*f(n-1)

⊕ bottom

f(1)= -18, f(n)= 6*f(n-1)

⊕ top

f(1)= 11, f(n)= f(n-1) + 22

Answer:

-12

Step-by-step explanation:

Answer:

7/200

Step-by-step explanation:

0.035= 35/1000= 7*5/200*5=7/200

Answer:

(-2)+(-5) = -7

Step-by-step explanation:

-2 + -5 = -7

but negative PLUS a negative equals a negative so the answer is going to be a negative, and just to keep in mind in the future that a negative PLUS a negative will give us a negative and negative TIMES a negative gives us a positive, and a positive PLUS a positive gives us a positive and a positive TIMES a positive gives us a positive and Negative times a positive equals a negative and negative PLUS a positive find the sum take the absolute value of each integer and then subtract the values.

The answer is -7 hope this helped! :)

Answer:

-7

Step-by-step explanation:

they add upp because they both negative

Answer:

5-i

Step-by-step explanation:

Product=multiplication

Let the complex number=x

(3+2i)*x=17+7i

x=17+7i / 3+2i

x=(17-7i)*(3-2i)/(3+2i)*(3+2i)

=51-34i+21i+14i^2 / 9+6i+6i+4i^2

=51+13i+14i^2 / 9+12i+4i^2

= (51+14 - 13i) / 13

= (65 -13i) / 13

= 65 / 13 - 13 i / 13

= 5 - i.

Answer:

option 3

Step-by-step explanation:

x = 2 is a vertical line with an x-intercept of (2, 0) so the answer is Option 3.

Answer:

Option 3

Step-by-step explanation:

The value of x will always be 2. Y can be anything it wants to be and x will still be 2 no matter what, You could pick multiple points on the line for each graph, and only Option 3 will have x always being 2.

Answer:

16

Step-by-step explanation:

The right triangle shown is a 30:60:90 triangle.

30:60:90 right triangles have a 1:sqrt(3):2 ratio between their sides.

Since the side opposite from the 30 degree is 8, and x is opposite from the 90 degree angle, 8 and x have a 1:2 ratio, or 8:16.

Answer:2

Step-by-step explanation:

3y+ 7= 13

3y= 13 - 7

3y= 6

Y = 6/3

Y= 2

Answer:

2.5

Step-by-step explanation:

[tex]9(u-2)+1.5u=8.25 \\\\9u-18+1.5u=8.25\\\\10.5u-18=8.25\\\\10.5u=26.25\\\\u=2.5[/tex]

Hope this helps!

Answer: The image is (6,-3)

Step-by-step explanation:

The coordinates of R is  ( 4,-2)  and to find the image using the scale factor 1.5 you will multiply the x coordinates by 1.5 and the y coordinate also by 1.5 to have the new image of R.

4 * 1.5 = 6

-2 * 1.5 = -3

The new coordinates care (6, -3)

Answer:

x = -30/7

Step-by-step explanation:

-7x+3y=30

Let y=0

-7x +0 = 30

Divide by -7

-7x /-7 = 30/-7

x = -30/7

Answer:

[tex]-\frac{30}{7}[/tex]

Step-by-step explanation:

y equals zero => y = 0

-7x+3y=30

-7x +3.0 = 30

-7x + 0 = 30

-7x = 30

-7x/-7 = 30/-7

x = -30/7

Hope this helps ^-^

Answer: D

Step-by-step explanation:

In order to increase each ticket by $2, you are ADDING 2 to each value.

So you create a matrix of all 2's and add that to the given matrix.

[tex]\left[\begin{array}{cc}2&2\\2&2\\2&2\end{array}\right] +\left[\begin{array}{cc}8&10\\12&16\\6&8\end{array}\right]\quad =\quad \large \left[\begin{array}{cc}10&12\\14&18\\8&10\end{array}\right][/tex]

Answer:

Unit 8 test answers

Step-by-step explanation:

1: a.)3x4

2:b.)

3:a.)

4:b.)

5:c.) matrix CD would have the dimensions 7x7

6: a.)

7:67

8:c.)

9:b.) Scott sold 1 van

10:d.)

4yd^2

2yd^2

6yd^2

Step-by-step explanation:

Rule: height x base/2

The area of the big triangle=2 x 4/2 = 4 yd^2

The area of the small one= 2 x2/2 =2yd^2

The total area of the trapezoid is the sum of these areas= 2+4=6yd^2

Answer:

√130 is the distance between (9,-3) (0,-10)

Step-by-step explanation:

[tex]y = {x}^{2} - 18 \\ y + 18 = {x}^{2} \\ square \: root \: both \: sides \: \\ \sqrt{y + 18} = \sqrt{ {x}^{2} } [/tex]

[tex]x = \sqrt{y + 18} [/tex]

Answer:

√y + 18 = x

Step-by-step explanation:

Let us solve it now.

y = x² - 18

Take -18 to the left side

y + 18 = x²

Now remove the square of x

√y + 18 = x

Answer:

2 parents are required

Step-by-step explanation:

Answer:

semen.............

Answer:

(a)24

(b)8

(c)4

Step-by-step explanation:

Number of STudents in the Class = 36

Angle representing Students with Red Hair =40 degrees

Angle representing Students with Blonde Hair =240 degrees

Therefore:

(a)Number of Students with Blonde Hair

[tex]=\dfrac{240^\circ}{360^\circ} \times 36\\\\ =24$ students[/tex]

(b)Number of Students with Dark Hair

Angle representing students with dark hair = 360-(240+40)=80 degrees

Therefore:

Number of Students with Dark Hair

[tex]=\dfrac{80^\circ}{360^\circ} \times 36\\\\ =8$ students[/tex]

(c)Number of Students with Blonde Hair

[tex]=\dfrac{40^\circ}{360^\circ} \times 36\\\\ =4$ students[/tex]

There are 8 students that have blond hair

There are 24 students that have dark hair

There are 4 students that have red hair

Please find attached the pie chart used in answering this question

A pie chart is a graph that displays information in a circle. The circle is divided into slices which represent a numerical proportion. The sum of angles in a pie chart is 360 degrees

To determine the number of students with a type of hair, use this formula :

(degree of the slice that represents the hair type / 360) x total number of students in the class

Degree of the slice that represents blond hair = 360 - (240 + 40) = 80

Students that have blonde hair = [tex]\frac{80}{360}[/tex]  x 36 = 8

Students that have dark hair = [tex]\frac{240}{360}[/tex] x 36 = 24

Students that have red hair = [tex]\frac{40}{360}[/tex] x 36 = 4

To learn more about pie charts, please check : https://brainly.com/question/11433309?referrer=searchResults

Step-by-step explanation:

20fruits=100%

5fruits=?

5x100/20 5fruitsx5%

=24%

Answer:

P(3) = 0.0244

P(3) = 2.44%

the probability that all three selected have driven while under the influence of alcohol is 2.44% or 0.0244

Step-by-step explanation:

Given;

The probability that they have driven while under the influence of alcohol is;

P = 29% = 0.29

the probability that all three selected have driven while under the influence of alcohol is;

P(3) = P × P × P

P(3) = 0.29 × 0.29 × 0.29

P(3) = 0.024389

P(3) = 0.0244

P(3) = 2.44%

the probability that all three selected have driven while under the influence of alcohol is 2.44% or 0.0244

Answer:

The price p could be any of $8 or $15 .

Step-by-step explanation:

The equation is a relationship between the numbers of pencil sharpener x can sell each week and the price of each sharpener p.

x = 2300 - 100p

xp = 12000

therefore,

x = 12000/p

insert the value of x in the equation

x = 2300 - 100p

12000/p = 2300 - 100p

12000/p + 100p - 2300 = 0

multiply through by p

12000 + 100p² - 2300p = 0

100p² - 2300p + 12000 = 0

divide through by 100

p² - 23 + 120 = 0

Find the number that we can multiply to give 120 and add to give - 23. The number are -15 and - 8.

p² - 8p - 15p + 120 = 0

p(p - 8) - 15(p - 8) = 0

(p - 8)(p - 15)

p = 8 or 15

x = 2300 - 100p

x = 2300 - 100(8)

x = 2300 - 800

x = 1500  pencil sharpener sold

or

x = 2300 - 100(15)

x = 2300 - 1500

x = 800 pencil sharpener sold

The price could be any of $8 or $15 .

Answer:

The probability is 0.2326 or 23.26%.

Step-by-step explanation:

The probability that a random customer fills their tank with premium gas is:

[tex]P( prem\ \&\ fill) = 0.2*0.5=0.10[/tex]

The probability that a random customer fills their tank is given by:

[tex]P(fill)=P( reg\ \&\ fill)+P( mid\ \&\ fill)+P( prem\ \&\ fill)\\P(fill) = 0.5*0.3+0.3*0.6+0.2*0.5\\P(fill) = 0.43[/tex]

Therefore, the probability that a customer used premium gas given that hey have filled their tank is:

[tex]P(prem| fill) = \frac{P( prem\ \&\ fill) }{P(fill)} \\P(prem| fill) =\frac{0.10}{0.43}=0.2326[/tex]

The probability is 0.2326 or 23.26%.