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Firlakuza [10]
3 years ago
12

W many solutions does this linear system have?y = 2x – 5 –8x – 4y = –20

Mathematics
1 answer:
Brums [2.3K]3 years ago
5 0
Using substitution

-8x-4(2x-5)=-20
-8x-8x+20=-20
-16x+20=-20
-16x=-40
x=2.5

Plug x into one of the original equations.
y=2(2.5)-5
y=5-5
y=0

Final answer: 1 solution (2.5, 0)
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Use limits to find the area of the region bounded by the graph f(x)=4-2x^3 , the x-axis , and the vertical lines x=0 and x=1
gtnhenbr [62]

Answer:

\frac{7}{2} square units.

Step-by-step explanation:

We have to use limits to find the area of the region bounded by the graph f(x) = 4 - 2x^{3} , the x-axis, and the vertical lines x=0 and x=1.

So, the area will be

A = \int\limits^1_0 {(4 - 2x^{3})} \, dx

= [4x - \frac{x^{4}}{2} ]^{1} _{0}

= 4 - \frac{1}{2}

= \frac{7}{2} square units. (Answer)

3 0
4 years ago
Radical Expressions and Data Analysis Unit Portfolio
Gnoma [55]
TASK 1
a) Data and frequency table are attached in picture #1.

b) The histogram is attached in picture #2

c) As the intervals increase the number of pieces of mail received, the frequency decreases, therefore we can say that are received few pieces of mail <span>are received more often.

TASK 2
a) The list of breeds and weights are reported in picture #3. 
</span>
In order to find the mean, sum up all the weights and divide by 9:
m = (<span>8 + 10 + 15 + 29 + 32 + 75 + 77 + 80 + <span>85) / 9 = 45.67 lbs

In order to find the median, you need to select the central value of your distribution: since you have 9 values, the central one will be in the fifth position:
M = 32 lbs

In order to find the mode, you need to select the value which shows more frequently: in this case, every value shows only once, therefore the mode cannot be determined.

The data are best described by the mean because they are almost symmetrically distributed between the least and the biggest values, while the median is more towards the small-weight side of the distribution.
 
b) In order to have an average of 250 lbs, the tenth dog should weight 2089 lbs.

Indeed, if the average is 250 lbs for 10 dogs, it means that the total sum of their weights is 250 × 10 = 2500 lbs. We know that the sum of the first 9 dogs is 411 lbs, therefore, the tenth dog should weight 2500 - 411 = 2089 lbs.

TASK 3
The city picked is Baltimore, the year 2017.
The table is attached in picture #4.
</span></span>
a) The box-and-whisker plot is attached in picture #5.

b) The median is the central value of the distribution, which is: <span> 
42.4, 45.3, 46.8 | 54.7, 57.6, 66.0 | 69.1,  76.5,  80.6 | 85.8, 87.8, 90.0 </span>
where we marked with a tally the quartiles.

Since we have 12 values, the median will be the average between the two central values:
M = (66.0 + 69.1) / 2 = 67.1 °F

c) 7<span>5% of the temperatures are below 83.2 °F.
Indeed, this value represents the third quartile. The position of the third quartile can be found by the formula:
3/4 </span>· (n + 1) = 3/4 · (12 + 1) = 3/4 <span>· 13 = 9.75
Therefore, since we did not get in integer position, the third quartile will be the average between the numbers in position 9 and 10:
q</span>₀.₇₅ = (80.6 + 85.8) / 2 = 83.2 °F

d) 7<span>5% of the temperatures are above 50.8 °F.
Indeed, this value represents the first quartile. Similarly to point c), the position can be found by the formula:
1</span>/4 · (n + 1) = 1/4 <span>· 13 = 3.25
And therefore:
</span>q₀.₂₅ = (<span><span><span>46.8 + </span><span>54.7) / 2 = 50.8 °F.</span></span></span> 

e) Baltimore in 2017 had a median high temperature of 67.1 °F.
25% of the year the high temperatures were warmer than 83.2 °F, with no outlier above 90.0 °F which was the hottest temperature.
25% of the high temperatures were colder than 50.8 °F, with no outlier below 42.4 °F, which was the coldest high temperature.

6 0
4 years ago
The Earth completely rotates on its axis once every 24 hours.
strojnjashka [21]

Answer:

A)

62/3 = 20.67 hours

B)

60.00 hours

C)

2074.29 miles

Step-by-step explanation:

If we assume the earth is a perfect circle, then in a complete rotation the earth covers 360 degrees or 2π radians.

A)

In 24 hours the earth rotates through an angle of 360 degrees. We are required to determine the duration it takes to rotate through 310 degrees. Let x be the duration it takes the earth to rotate through 310 degrees, then the following proportions hold;

(24/360) = (x/310)

solving for x;

x = (24/360) * 310 = 62/3 = 20.67 hours

B)

In 24 hours the earth rotates through an angle of 2π radians. We are required to determine the duration it takes to rotate through 5π radians. Let x be the duration it takes the earth to rotate through 5π radians, then the following proportions hold;

(24/2π radians) = (x/5π radians)

Solving for x;

x = (24/2π radians)*5π radians = 60 hours

C)

If the diameter of the earth is 7920 miles, then in 24 hours a point on the equator will rotate through a distance equal to the circumference of the Earth. Using the formula for the circumference of a circle we have;

circumference = 2*π*R = π*D

                         = 7920π miles

Therefore, the speed of the earth is approximately;

(7920π miles)/(24 hours) = 330π miles/hr

The distance covered by a point in 2 hours will thus be;

330π * 2 = 660π miles = 2074.29 miles

8 0
3 years ago
Someone please help it’s a quiz :(
vova2212 [387]

Answer:3/2

Step-by-step explain

6 0
3 years ago
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