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3 years ago

How do you simplify -3 1/2- -12 1/4

Mathematics

1 answer:

astraxan [27]3 years ago

8 0

To make the problem simpler, turn it to an improper fraction.

-7/2--49/48

-7/2+49/48

They have to have same dnominator to add.

-168/48+49/48

-119/48

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A 75-gallon tank is filled with brine (water nearly saturated with salt; used as a preservative) holding 11 pounds of salt in so

Debora [2.8K]

Let $A(t)$ = amount of salt (in pounds) in the tank at time $t$ (in minutes). Then $A(0) = 11$ .

Salt flows in at a rate

$\left(0.6\dfrac{\rm lb}{\rm gal}\right) \left(3\dfrac{\rm gal}{\rm min}\right) = \dfrac95 \dfrac{\rm lb}{\rm min}$

and flows out at a rate

$\left(\dfrac{A(t)\,\rm lb}{75\,\rm gal + \left(3\frac{\rm gal}{\rm min} - 3.25\frac{\rm gal}{\rm min}\right)t}\right) \left(3.25\dfrac{\rm gal}{\rm min}\right) = \dfrac{13A(t)}{300-t} \dfrac{\rm lb}{\rm min}$

where 4 quarts = 1 gallon so 13 quarts = 3.25 gallon.

Then the net rate of salt flow is given by the differential equation

$\dfrac{dA}{dt} = \dfrac95 - \dfrac{13A}{300-t}$

which I'll solve with the integrating factor method.

$\dfrac{dA}{dt} + \dfrac{13}{300-t} A = \dfrac95$

$-\dfrac1{(300-t)^{13}} \dfrac{dA}{dt} - \dfrac{13}{(300-t)^{14}} A = -\dfrac9{5(300-t)^{13}}$

$\dfrac d{dt} \left(-\dfrac1{(300-t)^{13}} A\right) = -\dfrac9{5(300-t)^{13}}$

Integrate both sides. By the fundamental theorem of calculus,

$\displaystyle -\dfrac1{(300-t)^{13}} A = -\dfrac1{(300-t)^{13}} A\bigg|_{t=0} - \frac95 \int_0^t \frac{du}{(300-u)^{13}}$

$\displaystyle -\dfrac1{(300-t)^{13}} A = -\dfrac{11}{300^{13}} - \frac95 \times \dfrac1{12} \left(\frac1{(300-t)^{12}} - \frac1{300^{12}}\right)$

$\displaystyle -\dfrac1{(300-t)^{13}} A = \dfrac{34}{300^{13}} - \frac3{20}\frac1{(300-t)^{12}}$

$\displaystyle A = \frac3{20} (300-t) - \dfrac{34}{300^{13}}(300-t)^{13}$

$\displaystyle A = 45 \left(1 - \frac t{300}\right) - 34 \left(1 - \frac t{300}\right)^{13}$

After 1 hour = 60 minutes, the tank will contain

$A(60) = 45 \left(1 - \dfrac {60}{300}\right) - 34 \left(1 - \dfrac {60}{300}\right)^{13} = 45\left(\dfrac45\right) - 34 \left(\dfrac45\right)^{13} \approx 34.131$

pounds of salt.

7 0

2 years ago

Help Me Find The X Please

Papessa [141]

Answer:

x = 16

y = 16 sqrt(3)

Step-by-step explanation:

Since this is a right triangle, we can use trig functions

sin theta = opp/hyp

sin 60 = y/ 32

Multiply each side by 32

32 sin 60 = y

32 ( sqrt(3) /2) = y

16 sqrt(2)

cos theta = adj/ hyp

cos 60 = x /32

32 cos 60 = x

32 (1/2) =x

16 =x

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3 years ago

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Find the measure of angle 3. measure of angle 1 = x measure of angle 2 = x-6

andrew11 [14]

The value of x would equal to 8

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3 years ago

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Ray Of Light [21]

Answer:

1. B.

2. C.

Step-by-step explanation:

1. It only has one cell so it needs to rely on other organisms in order for it to survive

2. Chloroplasts are only found in plants you can remember it by "Chloroplants"

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2 years ago

What is the solution to the equation?<br><br> 6x-3=3x+12

Alla [95]

Answer:

x=5

Step-by-step explanation:

Step 1: Subtract 3x from both sides.

6x−3−3x=3x+12−3x

3x−3=12

Step 2: Add 3 to both sides.

3x−3+3=12+3

3x=15

Step 3: Divide both sides by 3.

3x/3=15

x=5

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2 years ago

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