What is the answer ‍⬛ -1 1/5 + (-3/5)

2x+5d-9×2c+844+233+2×+78d

goldfiish [28.3K]

Answer:

−18c+83d+4x+1077

Step-by-step explanation:

combine all like terms

(2x+2x=4x)

(5d+78d=83d)

(-9*2c=-18c)

(1077=844+233)

5 0

3 years ago

assume the substance has a half-life of 11 years and the initial amount is 126 grams.How long will it be until only 15 % remains

Mumz [18]

(126) times (1/2 to the x/11 power) = 15% times 126

(1/2) to the x/11 power = 0.15

Take the log of both sides :

(x/11) times log(1/2) = log(0.15)

Multiply both sides by 11 :

'x' times log(1/2) = 11 x log(0.15)

Divide both sides by " log(1/2) " :

x = 11 x log(0.15)/log(1/2) = 30.107 years (rounded)

That's the time it takes for any-size sample of this substance
to decay to 15% of its original size.

5 0

2 years ago

Faron wants to paint the four walls in his bedroom. The room measures 12 ft long, 10 ft wide and 8 ft high. There are two doors

Rainbow [258]

Answer:

319 square feet.

Step-by-step explanation:

The walls of the room (the ones on the long side) have an area of 12 x 8 = 96 square feet each one. Thus, their area is 96 x 2= 192 square feet.

The other two walls have an area of 10 x 8 = 80 square feet each one. Thus, their area combined is 80 x 2 = 160 square feet.

Therefore, we have that the total area of the four walls is

192 +160 = 352 square feet

However, we have a door and a window that won't be painted.

The area of the door is: 3 x 7 =21 square feet

The area of the window is 3 x 4 = 12 square feet

Thus, the total amount of area that won't be painted is

21 + 12 = 33 square feet.

So we are going to take the total area minus the area that won't be painted to know the total area that Faron will pain:

352 - 33 = 319 square feet.

Thus, she will paint 319 square feet

4 0

3 years ago

Mario can eat 21 hot dogs in 6 minutes. At the same place, how many minutes would it take him to eat 35 hot dogs?

anyanavicka [17]

Answer:

10 minutes

Step-by-step explanation:

Mario can eat e21 hot dog in 6 minutes

Let 35 hot dog eats in x minutes :

$\frac{35}{x} =\frac{21}{6} \\x=\frac{35(6)}{21} \\x=10 min$

Therefore, mario would eat 35 dogs in 10 min.

6 0

2 years ago

The daily average temperature in Santiago, Chile, varies over time in a periodic way that can be modeled approximately by a trig

natali 33 [55]

Answer:

a) the trigonometric function is;

$y = 7.5 sin ( \frac{2 \pi}{365}t + \frac{337 \pi}{730})+ 21.5$

b) $y = 28.36^0 \ C$ ( to two decimal places)

Step-by-step explanation:

This data can be represented by the sinusoidal function of the form :

$\mathbf{y = A sin (Bt -C)+D}$

where A = amplitude and which can be determined via the formula:

$A = \dfrac{largest \ temperature - lowest \ temperature}{2}$

$A = \dfrac{29-14}{2}$

$A = \dfrac{15}{2}$

A = 7.5° C

where B = the frequency;

Since the data covers a period of 3 days ; then $\dfrac{2 \pi}{B } =365$

$B = \dfrac{2 \pi}{365}$ ( where 365 is the time period )

The vertical shift is found by the equation D;

D = $\frac{largest \ temperature + lowest \ temperature}{2}$

D = $\frac{29+14}{2}$

D = 21.5

Replacing the values of A ; B and D into the above sinusoidal function; we have :

$y = 7.5 sin (\frac{2 \pi}{365}t -C) + 21.5$

From the question; when it is 7th of the year ( i.e January 7);

t = 7 and the temperature (y) = 29° C

replacing that too into the above equation; we have:

$29= 7.5 sin (\frac{2 \pi}{365}*7 -C) + 21.5$

$29= 7.5 sin (\frac{14 \pi}{365} -C) + 21.5$

$\frac{29-21.5}{7.5}= sin (\frac{14 \pi}{365} -C)$

$1= sin (\frac{14 \pi}{365} -C)$

$sin^{-1}(1)= (\frac{14 \pi}{365} -C)$

$\frac{\pi}{2}= (\frac{14 \pi}{365} -C)$

$C= (\frac{14 \pi}{365} -\frac{\pi}{2})$

$C= (\frac{28 \pi- 365 \pi}{730} )$

$C= \frac{-337 \pi}{730}$

Thus; the trigonometric function is;

$y = 7.5 sin ( \frac{2 \pi}{365}t + \frac{337 \pi}{730})+ 21.5$

Similarly; to determine the temperature o Jan 31; i.e when t= 31 ; we have :

$y = 7.5 sin ( \frac{2 \pi}{365}*31+ \frac{337 \pi}{730})+ 21.5$

$y = 7.5 sin ( \frac{62 \pi}{365}+ \frac{337 \pi}{730})+ 21.5$

$y = 7.5 sin ( \frac{124 \pi+ 337 \pi }{730})+ 21.5$

$y = 7.5 sin ( \frac{461 \pi }{730})+ 21.5$

$y = 7.5 *( 0.915)+ 21.5$

$y = 6.8689+ 21.5$

$y = 28.36^0 \ C$ ( to two decimal places)

7 0

2 years ago

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