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Bess [88]
2 years ago
5

HELP PLSSS I CANT DO THIS HOMWORK

Mathematics
1 answer:
kvasek [131]2 years ago
8 0

Answer:

B=-6

Step-by-step explanation:

-21+9=-12

-12/2=-6

You can check it.

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What's the missing number?What is the rule?
MrMuchimi
Ok so for 1000m= 1km that means since 500 is half of 1000, 1/2 is half of 1
6 0
3 years ago
Which if any of the points is a whole of F (X)?
Alla [95]

Answer:

i think it x² so it can be. ot correct

3 0
1 year ago
Suppose the clean water of a stream flows into Lake Alpha, then into Lake Beta, and then further downstream. The in and out flow
Gala2k [10]

Answer:

a) dx / dt = - x / 800

b) x = 500*e^(-0.00125*t)

c) dy/dt = x / 800 - y / 200

d) y(t) = 0.625*e^(-0.00125*t)*( 1  - e^(-4*t) )

Step-by-step explanation:

Given:

- Out-flow water after crash from Lake Alpha = 500 liters/h

- Inflow water after crash into lake beta = 500 liters/h

- Initial amount of Kool-Aid in lake Alpha is = 500 kg

- Initial amount of water in Lake Alpha is = 400,000 L

- Initial amount of water in Lake Beta is = 100,000 L

Find:

a) let x be the amount of Kool-Aid, in kilograms, in Lake Alpha t hours after the crash. find a formula for the rate of change in the amount of Kool-Aid, dx/dt, in terms of the amount of Kool-Aid in the lake x:

b) find a formula for the amount of Kook-Aid in kilograms, in Lake Alpha t hours after the crash

c) Let y be the amount of Kool-Aid, in kilograms, in Lake Beta t hours after the crash. Find a formula for the rate of change in the amount of Kool-Aid, dy/dt, in terms of the amounts x,y.

d) Find a formula for the amount of Kool-Aid in Lake Beta t hours after the crash.

Solution:

- We will investigate Lake Alpha first. The rate of flow in after crash in lake alpha is zero. The flow out can be determined:

                              dx / dt = concentration*flow

                              dx / dt = - ( x / 400,000)*( 500 L / hr )

                              dx / dt = - x / 800

- Now we will solve the differential Eq formed:

Separate variables:

                              dx / x = -dt / 800

Integrate:

                             Ln | x | = - t / 800 + C

- We know that at t = 0, truck crashed hence, x(0) = 500.

                             Ln | 500 | = - 0 / 800 + C

                                  C = Ln | 500 |

- The solution to the differential equation is:

                             Ln | x | = -t/800 + Ln | 500 |

                                x = 500*e^(-0.00125*t)

- Now for Lake Beta. We will consider the rate of flow in which is equivalent to rate of flow out of Lake Alpha. We can set up the ODE as:

                  conc. Flow in = x / 800

                  conc. Flow out = (y / 100,000)*( 500 L / hr ) = y / 200

                  dy/dt = con.Flow_in - conc.Flow_out

                  dy/dt = x / 800 - y / 200

- Now replace x with the solution of ODE for Lake Alpha:

                  dy/dt = 500*e^(-0.00125*t)/ 800 - y / 200

                  dy/dt = 0.625*e^(-0.00125*t)- y / 200

- Express the form:

                               y' + P(t)*y = Q(t)

                      y' + 0.005*y = 0.625*e^(-0.00125*t)

- Find the integrating factor:

                     u(t) = e^(P(t)) = e^(0.005*t)

- Use the form:

                    ( u(t) . y(t) )' = u(t) . Q(t)

- Plug in the terms:

                     e^(0.005*t) * y(t) = 0.625*e^(0.00375*t) + C

                               y(t) = 0.625*e^(-0.00125*t) + C*e^(-0.005*t)

- Initial conditions are: t = 0, y = 0:

                              0 = 0.625 + C

                              C = - 0.625

Hence,

                              y(t) = 0.625*( e^(-0.00125*t)  - e^(-0.005*t) )

                             y(t) = 0.625*e^(-0.00125*t)*( 1  - e^(-4*t) )

6 0
3 years ago
Inside Kasi’s house, the temperature was 20°C. She stepped outside, where the temperature was 22°C cooler. Which expression repr
Ksju [112]

Answer:

B

Step-by-step explanation:

Hotter = Temperature goes up

Colder = Temperature goes down

Since it's getting cooler outside, temperature drops

20°C - 22°C= -2°C

5 0
3 years ago
Micheal is three time as old as Jean in seven year he will be twice old as she will be then how old are they both
PtichkaEL [24]

Answer:

Michael is 21 years old while Jean is 7 years old.

Step-by-step explanation:

Given that Micheal is three times as old as Jean, but in seven years he will be twice old as she will be, to determine how old are they both at this time, the following calculation must be performed:

M = 3J

M + 7 = 2J + 7

7 = 1/3

7 x 3 = 21

21 + 7 = 28

7 + 7 = 14

21 / 7 = 3

28 / 14 = 2

 

Therefore, Michael is 21 years old while Jean is 7 years old.

5 0
3 years ago
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