A system of equations is shown below: Equation A: 3c = d − 8 Equation B: c = 4d + 8 Which of the following steps should be performed to eliminate variable d first?

Answer:

A) cooling constant =  0.0101365

B) [tex]\frac{df}{dt} = k ( 60 - F )[/tex]

c)  F(t) = 60 + 77.46[tex]e^{0.0101365t}[/tex]

D)137.46 ⁰

Step-by-step explanation:

water temperature = 60⁰F

temperature of Bar after 20 seconds = 120⁰F

temperature of Bar after 60 seconds = 100⁰F

A) Determine the cooling constant K

The newton's law of cooling is given as

= [tex]\frac{df}{dt} = k(60 - F)[/tex]

= ∫ [tex]\frac{df}{dt}[/tex] = ∫ k(60 - F)

= ∫ [tex]\frac{df}{60 - F}[/tex] = ∫ kdt

= In (60 -F) = -kt - c

       60 - F = [tex]e^{-kt-c}[/tex]

      60 - F = [tex]C_{1} e^{-kt}[/tex]       ( note : [tex]e^{-c}[/tex] is a constant )

after 20 seconds

[tex]C_{1}e^{-k(20)}[/tex] = 60 - 120 = -60  

therefore [tex]C_{1} = \frac{-60}{e^{-20k} }[/tex] ------- equation 1

after 60 seconds

[tex]C_{1} e^{-k(60)}[/tex] = 60 - 100 = - 40  

therefore [tex]C_{1} = \frac{-40}{e^{-60k} }[/tex] -------- equation 2

solve equation 1 and equation 2 simultaneously

= [tex]\frac{-60}{e^{-20k} }[/tex] = [tex]\frac{-40}{e^{-60k} }[/tex]

= 6[tex]e^{20k}[/tex] = 4[tex]e^{60k}[/tex]

= [tex]\frac{6}{4} e^{40k}[/tex] = In(6/4) = 40k

cooling constant (k) = In(6/4) / 40 = 0.40546 / 40 = 0.0101365

B) what is the differential equation  satisfied

substituting the value of k into the newtons law of cooling)

60 - F = [tex]C_{1} e^{0.0101365(t)}[/tex]  

F(t) = 60 - [tex]C_{1} e^{0.0101365(t)}[/tex]

The differential equation that the temperature F(t) of the bar

[tex]\frac{df}{dt} = k ( 60 - F )[/tex]

C) The formula for F(t)

t = 20 , F = 120

F(t ) = 60 - [tex]C_{1} e^{0.0101365(t)}[/tex]

120 = 60 - [tex]C_{1} e^{0.0101365(t)}[/tex]

[tex]C_{1} e^{0.0101365(20)}[/tex] = 60

[tex]C_{1} = 60 * 1.291[/tex] = 77.46

C1 = - 77.46⁰ as the temperature is decreasing

The formula for f(t)

= F(t) = 60 + 77.46[tex]e^{0.0101365t}[/tex]

D) Temperature of the bar at the moment it is submerged

F(0) = 60 + 77.46[tex]e^{0.01013659(0)}[/tex]

F(0) = 60 + 77.46(1)

     = 137.46⁰

Answer:

I got 45, but I may be wrong.

Step-by-step explanation:

When a number is even, the number must end in an even number. Here, the even numbers are 4 and 6, so the numbers we are going to create are all going to end in 4 and 6.

To answer this question, we just have to find as many possible combinations following the guidelines provided.

334

344

354

364

374

434

444

454

464

474

534

544

554

564

574

634

644

654

664

674

336

346

356

366

376

436

446

456

466

476

536

546

556

566

576

636

646

656

666

676

736

746

756

766

776

Answer:

x = 64

Step-by-step explanation:

A circle equal 360 degrees

180 + 90 + x + 26 = 360

Combine like terms

296+x = 360

Subtract 296 from each side

296+x-296 = 360-296

x = 64

Answer:

x=0

Step-by-step explanation:

If the slope is undefined, the line is vertical

vertical lines are of the form

x =

Since the point is (0,6)

x=0

Answer:  i) θ = 30°, 60°, 210°, & 240°

              ii) θ = 20° &  200°

Step-by-step explanation:

i) sin (2θ) = cos 30°

[tex]\sin(2\theta)=\dfrac{\sqrt3}{2}\\\\.\quad 2\theta=\sin^{-1}\bigg(\dfrac{\sqrt3}{2}\bigg)\\\\.\quad 2\theta=60^o\qquad 2\theta=120^o\\\\.\quad \theta=30^o\qquad \theta=60^o[/tex]

To include all of the solutions for one rotation, add 360/2 = 180 to the solutions above.   θ = 30°, 60°, 210°, 240°

If you need ALL of the solutions (more than one rotation), add 180n to the solutions.   θ = 30° + 180n   &   60° + 180n

*********************************************************************************************

ii) cos α = sin (50 + α)

Use the Identity: cos α = sin (90 - α)

Use Transitive Property to get:   sin (50° + α) = sin (90° - α)

50° + α = 90° - α

50° + 2α = 90°

        2α = 40°

          α = 20°

To find all solutions for one rotation, add 360/2 = 180 to the solution above.

α = 20°, 200°

If you need ALL of the solutions (more than one rotation), add 180n to the solution. α = 20° + 180n

Answer:

Im not 100% sure, but I think it is:

No

No

No

Yes

Answer:

D

Step-by-step explanation:

this is the only one inside the overlapping inequalitlies

Answer:

5

Step-by-step explanation:

Answer:

[tex]\boxed{13}[/tex] pages

Step-by-step explanation:

Divide the total number of pages by 5 to get how many sets of every 5 pages will contain 2/3 of a page of advertisements.

[tex]\frac{98}{5} = 19.6[/tex]

Multiply this value by [tex]\frac{2}{3}[/tex] to get the total number of pages.

[tex]19.6 * \frac{2}{3} \approxeq 13[/tex] pages

Answer:

1. k=0

2. yes, result is still a polynomial.

3. yes, f and g must have the same degree to have deg(f+g) < deg(f) or deg(g)

Step-by-step explanation:

1. for what constant k must f(k) always equal the constant term of f(x) for any polynomial f(x)

for k=0 any polynomial f(x) will reduce f(k) to the constant term.

2. If we multiply a polynomial by a constant, is the result a polynomial?

Yes, If we multiply a polynomial by a constant, the result is always a polynomial.

3. if deg(f+g) is less than both deg f and deg g, then must f and g have the same degree?

Yes.  

If

deg(f+g) < deg(f) and

deg(f+g) < deg(g)

then it means that the two leading terms cancel out, which can happen only if f and g have the same degree.

Step-by-step explanation:

angle A = angle B( Corresponding angles)

so,

5x - 5 = 3x + 13

=> 5x - 3x = 13 + 5

=> 2x = 18

=> x = 9

angle B = 3x + 13 = (3×9) + 13 = 27 + 13 = 40

Answer:

x=9, ∠B=40

Step-by-step explanation:

In this case, ∠A≅∠B, as they are corresponding angles. Therefore, if you set up the equation to be 5x-5=3x+13,

2x=18, x=9

∠B=3(9)+13=27+13=40

Answer:

460

Step-by-step explanation:

Answer:

460

Step-by-step explanation:

Answer:

The graph of g is the graph of f shifted up by 3 units.

Step-by-step explanation:

Consider the graph of a function r with real numbers k and h.

Transformation Effect

r(x) + k shifts the graph up k units

r(x) - k shifts the graph down k units

r(x + h) shifts the graph to the left h units

r(x - h) shifts the graph to the right h units

It is given that g(x) = f(x) + 3. Therefore, the graph of g is the graph of f shifted up by 3 units.

Answer: c(x) = $50*x + $24

Step-by-step explanation:

First, this situation can be modeled with a linear equation like:

c(x) = s*x + b

where c is the cost, s is the slope, x is the number of cubic yards of mulch bought, and b is the y-intercept ( a constant that no depends on the number x)

Then we know that:

The company charges $50 per cubic yard, so the slope is $50

A delivery charge of $24, this delivery charge does not depend on x, so this is the y-intercept.

Then our equation is:

c(x) = $50*x + $24

This is:

"The cost of buying x cubic yards of mulch"

Answer:

x ≥ 4 AND  x + y ≤ 10

Step-by-step explanation:

If you need up to 10 volunteers, then you can take 10 or less. If we add y and x, we'll get the total amount of people, therefore making the inequality:

x + y ≤ 10.

Now, he needs no fewer than 4 females, so he can take 4 or greater. This means that x should be greater than or equal to 4.

x ≥ 4.

Nothing was mentioned about how many males he needed (y) so these two inequalities match the situation.

Hope this helped!

Answer:

sin⁴x - sin²x = cos⁴x - cos²x

Solve the right hand side of the equation

That's

sin⁴x - sin²x

From trigonometric identities

So we have

sin⁴x - ( 1 - cos²x)

sin⁴x - 1 + cos²x

sin⁴x = ( sin²x)(sin²x)

That is

( sin²x)(sin²x)

So we have

( 1 - cos²x)(1 - cos²x) - 1 + cos²x

Expand

1 - cos²x - cos²x + cos⁴x - 1 + cos²x

1 - 2cos²x + cos⁴x - 1 + cos²x

Group like terms

That's

cos⁴x - 2cos²x + cos²x + 1 - 1

Simplify

We have the final answer as

So we have

Since the right hand side is equal to the left hand side the identity is true

Hope this helps you

Answer:

(x – 4)^2 + (y + 7)^2 = 16

Step-by-step explanation:

The formula of a circle is:

(x – h)^2 + (y – k)^2 = r^2

(h, k) represents the coordinates of the center of the circle

r represents the radius of the circle

If you plug in the given information, you get:

(x – 4)^2 + (y – (-7))^2 = 4^2

which simplifies into:

(x – 4)^2 + (y + 7)^2 = 16

Answer:

[tex]\boxed{7^{\frac{3}{2} } \times 4}[/tex]

Step-by-step explanation:

[tex]4 (\sqrt{7} )^3[/tex]

Square root can be written as a power.

[tex]4(7^{\frac{1}{2} })^3[/tex]

Multiply the exponents.

[tex]4(7^{\frac{3}{2} })[/tex]

Answer:

A (7^3/4)

Step-by-step explanation:

ed 2020

Answer:

RS = 8

Step-by-step explanation:

Given:

Secant QU = internal secant segment PU + external secant segment PQ = 7 + 9 = 16

Secant QS = internal secant segment RS + external secant segment RQ = (3x - 5) + 8

To find the measure of RS, we need to find the value of x.

Thus, recall the "Two Secant Theorem"

According to the theorem,

(RS + RQ)*RQ = (PU + PQ)*PQ

Thus,

[tex] (3x - 5 + 8)*8 = (7 + 9)*9 [/tex]

[tex] (3x + 3)*8 = (16)*9 [/tex]

[tex] 24x + 24 = 144 [/tex]

Subtract 24 from both sides

[tex] 24x + 24 - 24 = 144 - 24 [/tex]

[tex] 24x = 120 [/tex]

Divide both sides by 24

[tex] \frac{24x}{24} = \frac{120}{24} [/tex]

[tex] x = 5 [/tex]

Plug in the value of x into (3x - 5) to find the measure of RS

RS = 3(5) - 5 = 15 - 7

RS = 8

Answer:

A 98% confidence interval estimate for the difference in mean speed of the films is [-0.042, 0.222].

Step-by-step explanation:

We are given that Eight samples of each film thickness are manufactured in a pilot production process, and the film speed (in microjoules per square inch) is measured.

For the 25-mil film, the sample data result is: Mean Standard deviation 1.15 0.11 and For the 20-mil film the data yield: Mean Standard deviation 1.06 0.09.

Firstly, the pivotal quantity for finding the confidence interval for the difference in population mean is given by;

                     P.Q.  =  [tex]\frac{(\bar X_1 -\bar X_2)-(\mu_1- \mu_2)}{s_p \times \sqrt{\frac{1}{n_1}+\frac{1}{n_2} } }[/tex]  ~  [tex]t__n_1_+_n_2_-_2[/tex]

where, [tex]\bar X_1[/tex] = sample mean speed for the 25-mil film = 1.15

[tex]\bar X_1[/tex] = sample mean speed for the 20-mil film = 1.06

[tex]s_1[/tex] = sample standard deviation for the 25-mil film = 0.11

[tex]s_2[/tex] = sample standard deviation for the 20-mil film = 0.09

[tex]n_1[/tex] = sample of 25-mil film = 8

[tex]n_2[/tex] = sample of 20-mil film = 8

[tex]\mu_1[/tex] = population mean speed for the 25-mil film

[tex]\mu_2[/tex] = population mean speed for the 20-mil film

Also,  [tex]s_p =\sqrt{\frac{(n_1-1)s_1^{2}+ (n_2-1)s_2^{2}}{n_1+n_2-2} }[/tex] = [tex]\sqrt{\frac{(8-1)\times 0.11^{2}+ (8-1)\times 0.09^{2}}{8+8-2} }[/tex] = 0.1005

Here for constructing a 98% confidence interval we have used a Two-sample t-test statistics because we don't know about population standard deviations.

So, 98% confidence interval for the difference in population means, ([tex]\mu_1-\mu_2[/tex]) is;

P(-2.624 < [tex]t_1_4[/tex] < 2.624) = 0.98  {As the critical value of t at 14 degrees of

                                             freedom are -2.624 & 2.624 with P = 1%}  

P(-2.624 < [tex]\frac{(\bar X_1 -\bar X_2)-(\mu_1- \mu_2)}{s_p \times \sqrt{\frac{1}{n_1}+\frac{1}{n_2} } }[/tex] < 2.624) = 0.98

P( [tex]-2.624 \times {s_p \times \sqrt{\frac{1}{n_1}+\frac{1}{n_2} } }[/tex] < [tex]2.624 \times {s_p \times \sqrt{\frac{1}{n_1}+\frac{1}{n_2} } }[/tex] <  ) = 0.98

P( [tex](\bar X_1-\bar X_2)-2.624 \times {s_p \times \sqrt{\frac{1}{n_1}+\frac{1}{n_2} } }[/tex] < ([tex]\mu_1-\mu_2[/tex]) < [tex](\bar X_1-\bar X_2)+2.624 \times {s_p \times \sqrt{\frac{1}{n_1}+\frac{1}{n_2} } }[/tex] ) = 0.98

98% confidence interval for ([tex]\mu_1-\mu_2[/tex]) = [ [tex](\bar X_1-\bar X_2)-2.624 \times {s_p \times \sqrt{\frac{1}{n_1}+\frac{1}{n_2} } }[/tex] , [tex](\bar X_1-\bar X_2)+2.624 \times {s_p \times \sqrt{\frac{1}{n_1}+\frac{1}{n_2} } }[/tex] ]

= [ [tex](1.15-1.06)-2.624 \times {0.1005 \times \sqrt{\frac{1}{8}+\frac{1}{8} } }[/tex] , [tex](1.15-1.06)+2.624 \times {0.1005 \times \sqrt{\frac{1}{8}+\frac{1}{8} } }[/tex] ]

 = [-0.042, 0.222]

Therefore, a 98% confidence interval estimate for the difference in mean speed of the films is [-0.042, 0.222].

Since the above interval contains 0; this means that decreasing the thickness of the film doesn't increase the speed of the film.

Answer:

3.22222......  = [tex]\frac{29}{9}[/tex]

Step-by-step explanation:

In this question we have to convert the number given in recurrent decimals into fraction.

Recurrent decimal number is 3.22222.......

Let x = 3.2222.........   -------(1)

Multiply this expression by 10.

10x = 32.2222........... -------(2)

Now subtract the expression (1) from (2),

10x = 32.22222.....

   x = 3.22222.......

9x = 29

x = [tex]\frac{29}{9}[/tex]

Therefore, recurrent decimal number can be written as [tex]\frac{29}{9}[/tex] which is in the form of [tex]\frac{p}{q}[/tex].

Answer:

The slope is -4.

Step-by-step explanation:

The values -2 and -6 are 4 values apart.

The values -4 and -3 are 1 value apart.

Since the second coordinate is lower than the first one, the slope of this is negative.

4 / 1 = 1

Negating 1 gets us -1.

Hope this helped!

Answer:

[tex] \frac{y}{x} = \frac{ - 4}{1} = - 4[/tex]

Step-by-step explanation:

[tex]x = ( - 3) - ( - 4) = 1[/tex]

[tex]y = ( - 6) - ( - 2) = - 4[/tex]

Answer:

The p-value is 2.1%.

Step-by-step explanation:

We are given that a study is done to see if the average age a "child" moves permanently out of his parents' home in the United States is at most 23. 43 U.S. Adults were surveyed.

The sample average age was 24.2 with a standard deviation of 3.7.

Let [tex]\mu[/tex] = true average age a "child" moves permanently out of his parents' home in the United States.

So, Null Hypothesis, [tex]H_0[/tex] : [tex]\mu \leq[/tex] 23      {means that the average age a "child" moves permanently out of his parents' home in the United States is at most 23}

Alternate Hypothesis, [tex]H_A[/tex] : [tex]\mu[/tex] > 23      {means that the average age a "child" moves permanently out of his parents' home in the United States is greater than 23}

The test statistics that will be used here is One-sample t-test statistics because we don't know about population standard deviation;

                            T.S.  =  [tex]\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }[/tex]  ~ [tex]t_n_-_1[/tex]

where, [tex]\bar X[/tex] = sample average age = 24.2

            s = sample standard deviation =3.7

            n = sample of U.S. Adults = 43

So, the test statistics =  [tex]\frac{24.2-23}{\frac{3.7}{\sqrt{43} } }[/tex]  ~  [tex]t_4_2[/tex]

                                    =  2.127

The value of t-test statistics is 2.127.

Now, the p-value of the test statistics is given by;

         P-value = P( [tex]t_4_2[/tex] > 2.127) = 0.021 or 2.1%

Answer:

Step-by-step explanation:

pt=700 is basically evaluate it form the bottom to the top and u must mark me as brainly

surface area of a equilateral by hand a 140.4 cm and 9cm

Answer:

A=1,728

Step-by-step explanation:

To find the area of a prism, you must find the area of one side, then multiply it by so it would be Width*Hight*Depth, W*H*D.

The width is 12, the hight is 12, and the depth is 12 so you can write

A=12*12*12

Multiply 12 by 12

A=144*12

Multiply 12 by 144 to get your final total area

A=1,728

Hope this helps, feel free to ask follow-up questions if confused.

Have a good day! :)

Answer:

0.992774 ≅ .993

Step-by-step explanation:

a²+b²=c²

a=x

b=3

c=3.16

x²+3²=3.16²

x²+9=9.9856

x²=.9856

x=0.992774

x≅0.993

Answer:

[tex]z=(-\sqrt{3}+i)^6[/tex] = -64

Step-by-step explanation:

You have the following complex number:

[tex]z=(-\sqrt{3}+i)^6[/tex]       (1)

The Demoivres theorem stables the following:

[tex]z^n=r^n(cos(n\theta)+i sin(n\theta))[/tex]      (2)

In this case you have n=6

In order to use the theorem you first find r and θ, as follow:

[tex]r=\sqrt{3+1}=2\\\\\theta=tan^{-1}(\frac{1}{\sqrt{3}})=30\°[/tex]

Next, you replace these values into the equation (2) with n=6:

[tex]z^6=(2)^6[cos(6*30\°)+isin(6*30\°)]\\\\z^6=64[-1+i0]=-64[/tex]

Then, the solution is -64

Answer:

A) -64

Step-by-step explanation:

Edge 2021

Answer:

First answer.

Step-by-step explanation:

Multiply everything by 10, to get rid of the decimals.

Answer:

-16-5q

Step-by-step explanation:

-6+4q-6q-6+4q-6q-6+4q-6q= -18-6q

Answer:C

Step-by-step explanation: 100% correct I did it on Khan Academy