Solve the inequality 4x – 7 < 5

Answer:

a. 0.302 dB/s

b. 2.34 dB/s

c. 1.24 dB/s

Step-by-step explanation:

a) Find the rate of change of the sound pressure P with respect to time if W=7.2 and dW/dt = 0.5 at some given time t.

Since P = 10log(W/W₀), its rate of change with respect to time is

dP/dt = dP/dW × dW/dt

dP/dW = d[10logW - 10logW₀]/dt

dP/dW = d[10lnW/2.303 - 10logW₀]/dt

= 10/2.303W - 0

= 10/(2.303W)

dP/dt = dP/dW × dW/dt

dP/dt = 10/(2.303W) × dW/dt

Since dW/dt = 0.5 when W = 7.2, then

dP/dt = 10/(2.303 × 7.2) × 0.5

dP/dt = 10/16.5816 × 0.5

dP/dt = 0.603 × 0.5

dP/dt = 0.302 dB/s

b) If the variable sound power W is given by W = t² + t + 1, find the rate of change of the sound pressure P, at time t = 3s.

Since P = 10log(W/W₀), its rate of change with respect to time is

dP/dt = dP/dW × dW/dt

dP/dW = d[10logW - 10logW₀]/dt

dP/dW = d[10lnW/2.303 - 10logW₀]/dt

= 10/2.303W - 0

= 10/(2.303W)

and dW/dt = d(t² + t + 1)/dt = 2t + 1

So, dP/dt = dP/dW × dW/dt

dP/dt = 10/(2.303W) × (2t + 1)

dP/dt = 10(2t + 1)/(2.303W)

dP/dt = 10(2t + 1)/[2.303(t² + t + 1)]

we then substitute t = 3 into the equation

dP/dt = 10(2t + 1)/[2.303(t² + t + 1)]

dP/dt = 10(2(3) + 1)/[2.303((3)² + 3 + 1)]

dP/dt = 10(6 + 1)/[2.303(9 + 3 + 1)]

dP/dt = 10(7)/[2.303(13)]

dP/dt = 70/29.939

dP/dt = 2.34 dB/s

c) If W = cos 0.2t, find the rate of change of the sound pressure P, at time t = 15 (calculators in radians)

Since dP/dt = dP/dW × dW/dt and dP/dW = 10/(2.303W) and W = cos(0.2t), dW/dt = -0.2sin(0.2t)

So, dP/dt = dP/dW × dW/dt

dP/dt = 10/(2.303W) × -0.2sin(0.2t)

dP/dt = -20sin(0.2t)/(2.303W)

dP/dt = -20sin(0.2t)/(2.303cos(0.2t))

dP/dt = -20tan(0.2t)/2.303

when t = 15, we have

dP/dt = -20tan(0.2 × 15)/2.303

dP/dt = -20tan3/2.303

dP/dt = -20 × -0.1425/2.303

dP/dt = 2.8509/2.303

dP/dt = 1.238

dP/dt ≅ 1.24 dB/s

Multiply the amount of paint started with by the amount used:

2/3 x 1/2 = (2 x 1) / (3 x 2) = 2/6 = 1/3

There is 1/3 liter left

Answer:

Step-by-step explanation:

Answer:

d = 52°

Step-by-step explanation:

The two sides with little marks are congruent.

That means that the opposite angles are congruent.

One angle measures 76°.

The other to angles measure d each.

d + d + 76 = 180

2d + 76 = 180

2d = 104

d = 52

Answer:

Equation is C = 4P

Graph is shown below

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Explanation:

The equation is C = 4P since it costs $4 per person. We just multiply 4 with the number of people (P) to get the cost (C).

Let's say 0 people show up, so that means C = 4*P = 4*0 = 0

The input P = 0 leads to the output C = 0. This is basically the same as saying x = 0 leads to y = 0. The point (0,0) is on the graph.

Repeat for P = 1 and you'll find that C = 4. This is the same as x = 1 leading to y = 4. The point (1,4) is on the graph.

If you keep going for various values of P, you'll get corresponding values of C. It turns out that all you need are 2 points to graph this line. Plot (0,0) and (1,4) on the same xy grid. Draw a line through them to complete the graph.

The graph is shown below.

Answer:

The 30 minutes that she is changing the flat

Step-by-step explanation:

=====================================================

Explanation:

Set the expression equal to 100 and get everything to one side

[tex]d^2 - 12d + 45 = 100\\\\d^2 - 12d + 45 - 100 = 0\\\\d^2 - 12d - 55 = 0\\\\[/tex]

Now use the quadratic formula. We'll plug in a = 1, b = -12, c = -55.

[tex]\ d = \frac{-b\pm\sqrt{b^2-4ac}}{2a}\\\\\ d = \frac{-(-12)\pm\sqrt{(-12)^2-4(1)(-55)}}{2(1)}\\\\\ d = \frac{12\pm\sqrt{364}}{2}\\\\\ d \approx \frac{12\pm19.07878403}{2}\\\\\ d \approx \frac{12+19.07878403}{2}\ \text{ or } \ d \approx \frac{12-19.07878403}{2}\\\\\ d \approx \frac{31.07878403}{2}\ \text{ or } \ d \approx \frac{-7.07878401}{2}\\\\\ d \approx 15.53939201\ \text{ or } \ d \approx -3.53939201\\\\d \approx 15.54 \ \text{ or } \ d \approx -3.54[/tex]

We'll ignore the negative d value as we can't have a negative number of days.

This means d = 15.54 is the only approximate solution we'll consider.

If we plugged in d = 15, then,

d^2 - 12d + 45

(15)^2 - 12(15) + 45

90

This tells us that 90 masks were sold on day d = 15.

Now try d = 16

d^2 - 12d + 45

(16)^2 - 12(16) + 45

109

We see that 109 masks were sold on day d = 16. Somewhere between those days, 100 masks were sold. At the end of the 15th day, we got to 90. So in the middle of day 16 is when we reach the exact 100 mark we're after.

In short, we would round d = 15.54 up to d = 16 so that we clear the hurdle.

In other words, if you rounded d = 15.54 to d = 15, then you'd be 10 masks short of the goal. Besides, 15.54 rounds to 16 when rounding to the nearest whole number.

Answer:

It moved one space to the right , so it is a translation.

Step-by-step explanation:

shown below.

Answer:

Handling Data and probability

Answer:

a trinomial is a perfect square trinomial if it can be factorized into a binomial multiplies to itself. In a perfect square trinomial, two of your terms will be perfect squares.

Answer: Just create an account and you have unlimited skips.

Answer:

368.47

1686.56

Step-by-step explanation:

effective rate: .05/12=.00416666667

payment=x

[tex]16000=x\frac{1-(1+.00416666667)^{-48}}{.00416666667}\\x=368.47[/tex]

Interest:

368.47*48-16000=1686.56

Answer:

Answer:

368.47

1686.56

Step-by-step explanation:

effective rate: .05/12=.00416666667

payment=x

\begin{gathered}16000=x\frac{1-(1+.00416666667)^{-48}}{.00416666667}\\x=368.47\end{gathered}

16000=x

.00416666667

1−(1+.00416666667)

−48

x=368.47

Interest:

368.47*48-16000=1686.56

Answer:

bacteria 1

Step-by-step explanation:

i got it right

Answer:

90 kilometers

Step-by-step explanation:

https://www.bing.com/search?q=kilometers+are+there+in+9000000cm

Answer:

y= - 1/2 x-2 ( SEE IMAGE BELOW)

Step-by-step explanation:

FYI you can use the app photo math, you just take a pic of the problem and it gives you the answer and explains the steps and it is free.

Answer:

How do you write

x+2y=4

into slope intercept form?

Answer is:

y=−12x+2

Step-by-step explanation:

Slope intercept form can be represented as

y=mx+b

To get an equation into this form, we should try to get y all alone.

So then from x+2y=4

first, we can subtract x from both sidesand get 2y=−x+4

then, we can divide both sides by 2 to get it in slope intercept form

y=−12x+2

I think is like this. Hope it helps>3

Answer:

Step-by-step explanation:

BUG is 30 degrees more than GUY

So that means if <GUY = x

< BUG = <GUY + 30

Together they make 180 degrees

<BUG + <GUY = 180        Substitute for <BUG

<GUY + 30 <GUY = 180  Combine

2*<GUY + 30 = 180          Subtract 30 from both sides

2*<GUY = 150                   Divide by 2

<GUY = 150/2

<GUY = 75

<BUG = 75 + 30

<BUG = 105

Answer:

x = 10

y = 6

Step-by-step explanation:

x/2 - y/3 = 3 - - - (1)

4x - 3y = 22 - - - (2)

From (1):

x/2 - y/3 = 3

(3x - 2y)/6 = 3

3x - 2y = 18 - - - - (11)

4x - 3y = 22 - - - - (2)

Multiply (11) by 1.5

4.5x - 3y = 27 _____(111)

4x - 3y = 22 - - - (2)

Subtract :

0.5x = 5

x = 5 / 0.5 = 10

From :

4x - 3y = 22

Put x = 10

4(10) - 3y = 22

40 - 3y = 22

-3y = 22 - 40

-3y = - 18

y = 6

Answer:

Step-by-step explanation:

11 22 6 34 19

Answer:

4.575

Step-by-step explanation:

365.085/79.8=4.575

Answer:

Option 2: 660

Step-by-step explanation:

Multiply the three numbers together

Answer:

660mm 3

Step-by-step explanation:

Rectangular prism formula: V=LWH

15 x 11 x 4 = 660mm 3

Hope that helps <3

Answer:

B = 25 because 180-25-130 = 25 and all angles within triangle add to 180 degrees

a = 6  because the triangle is isosceles and we can see symmetry and draw this to prove on two opposite lines, therefore we can now find height easier.

c = 10. 876  because 130/2 = 65 degree and with new central height we can find Right Angle and using 6 x sin (65) = 5. 438 then we multiply by 2 to find c  

Then all you have to do is re-write and round to the nearest 10th and check the units and write degree sign where required.

Step-by-step explanation:

Answer:

angle w and angle v; angle x and angle y (option 1)

Step-by-step explanation:

the little arc things are what tell you two angles are corresponding m

angles w and v both have two arc drawing things.

angle x and y have one

and the other angles that aren't labeled have three

Answer:

It's a 90 angle, straight up and down, moving into straight right and left.

Answer:

The correct answer or value of xis 60

Step-by-step explanation:

12=x/5

or,12×5=x

or,60=x

Answer: 59.14706

Step-by-step explanation:

Answer:

59.14706 mL

Step-by-step explanation:

Formula is

for an approximate result, multiply the volume value by 237

which is 59.25

Step-by-step explanation:

(2x-y+3)(2x-y-3)=

4x²-2xy-6x-2xy+y²+3y+6x-3y-9=

4x²-4xy+y²-9=

(2x-y)²-9

Answer:The correct answer is m= and θ = 30º.

Step-by-step explanation:First, we must form a triangle whose hypotenuse is the radius r=1, its adjacent leg is m, its opposite leg is  and the angle is theta.

First, we calculate the angle with theta's breast:

sin (θ) =  

where H is the hypotenuse, in this case, the radio.

θ =  ()

θ = 30º

Now, we calculate the adjacent leg, which is equal to the x-coordinate of the point:

cos (θ) =  

m = cos 30º * H

m =  

m =  

Have a nice day!

Answer:

-5 =x

Step-by-step explanation:

0 = In(x + 6)

Raise each side to base e

e^0 = e^ ln (x+6)

1 = x+6

Subtract 6 from each side

1-6 = x

-5 =x

Answer:

Step-by-step explanation:

B

Answer:

Alanna is 32 years old

Step-by-step explanation:

Hi there!

We're given that Alix is 10 years older than Tamia and Alanna is twice as old as Tamia.

Since Alix and Alanna's ages are in relation to Tamia's, let's make Tamia's age x

Alix is 10 years older than Tamia, so Alix must be x+10 years old

Alanna is twice as old as Tamia, so she must be 2x years old

We're also given that Alix+Alanna+Tamia=74

When we substitute it with the expressions we have, it becomes:

x+x+10+2x=74

now combine like terms

4x+10=74

subtract 10 from both sides

4x=64

divide both sides by 4

x=16

We found the value of x (Tamia's age)

However, the problem asks for Alanna's age, which we have set as 2x

So Alanna is 2*16, or 32 years old

Hope this helps! :)

Answer:

32 years

Step-by-step explanation:

that is the procedure above