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beks73 [17]
1 year ago
6

Show and explain how replacing one equation by the sum of that equation and a multiple of the other produces a system with the s

ame solutions as the one shown. 8x + 7y = 39 4x – 14y = –68
Mathematics
1 answer:
telo118 [61]1 year ago
3 0

Answer:

(1/2, 5)

Step-by-step explanation:

8x + 7y = 39

-2(4x - 14y = -68)

-8x + 28y = 136

8x + 7y = 39

add the two equations together

35y = 175

y = 5

8x + 7(5) = 39

8x = 4

x = 1/2

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Anthony, Brian and Chris are hired for a job. If Anthony and Brian are working together they will finish the job in minutes. If
Tcecarenko [31]

Answer:

12.5

Step-by-step explanation:

Let  individual time taken by Anthony, Brian and Chris = t1 , t2 , t3 respectively

So, total time taken by A & B  = 1 / t1  + 1 / t2 , lets suppose = 10  {i}

Total time taken by A & C = 1 / t1  + 1 / t3 , lets suppose = 15 {ii}

Total time taken by B & C = 1 / t2  + 1 / t3 , lets suppose = 20 {iii}

From {i} , 1 / t2 = 10 - 1 / t1

From {ii} 1 / t1 = 15 - 1 / t3

By above two eqtns ,  1 / t2 = 10 - (15 - 1 / t3)

1 / t2 = 1 / t3 - 5

Putting in {iii} , 1 / t3 - 5 + 1 / t3 = 20

2 / t3 = 25

t3 = 12.5

5 0
2 years ago
A person is standing exactly 36 ft from a telephone pole. There is a 30° angle of elevation from the ground to the top of the po
nika2105 [10]

Answer:

20.78feet

Step-by-step explanation:

The question made us to understand that the man is standing and also there is angle of elevation, then we need to draw a right triangle having a base equal to 36 feet with an angle from the base to the top of the pole which is 30 degrees.

tan= opposite side / adjacent side

Let height of the pole =h

Tan(30)= h/36

But tan 30degree= 1/√3

h= 36 × 1/√3

h= 20.78feet

Therefore, the height of the pole= 20.78feet

CHECK THE ATTACHMENT FOR DETAILED FIGURE

7 0
1 year ago
Read 2 more answers
Barbara drives between Miami, Florida, and West Palm Beach, Florida. She drives 50 mi in clear weather and then encounters a thu
NeX [460]

Distance traveled in clear weather = 50 miles

Distance traveled in thunderstorm = 15 miles

Let speed in clear weather = x

⇒ Speed in thunderstorm = x-20

Total time taken for trip = 1.5 hours

We need to determine average speed in clear weather (i.e. x) and average speed in the thunderstorm (i.e. x-20 ).

Total time taken for trip = Time taken in clear weather + Time taken in thunderstorm

⇒ Total time taken for trip = \frac{Distance covered in clear weather}{Speed in clear weather} + \frac{Distance covered in thunderstorm}{Speed in thunderstorm}

⇒ 1.5 = \frac{50}{x} + \frac{15}{x-20}

⇒ 1.5 = \frac{50(x-20)+15(x)}{(x)(x-20)}

⇒ 15*x*(x-20) = 10*[50*(x-20)+15*x]

⇒ 15x² - 300x = 500x - 10,000 + 150x

⇒ 15x² - 300x = 650x - 10,000

⇒ 15x² - 950x + 10,000 = 0

⇒ 3x² - 190x + 2,000 = 0

The above equation is in the format of ax² + bx + c = 0

To determine the roots of the equation, we will first determine 'D'

D = b² - 4ac

⇒ D = (-190)² - 4*3*2,000

⇒ D = 36,100 - 24,000

⇒ D = 12,100

Now using the D to determine the two roots of the equation

Roots are: x₁ = \frac{-b+\sqrt{D}}{2a} ; x₂ = \frac{-b-\sqrt{D}}{2a}

⇒ x₁ = \frac{-(-190)+\sqrt{12,100}}{2*3} and x₂ = \frac{-(-190)-\sqrt{12,100}}{2*3}

⇒ x₁ = \frac{190+110}{6} and x₂ = \frac{190-110}{6}

⇒ x₁ = \frac{300}{6} and x₂ = \frac{80}{6}

⇒ x₁ = 50 and x₂ = 13.33

So speed in clear weather can be 50 mph or 13.33 mph. However, we know that in thunderstorm was 20 mph less than speed in clear weather.

If speed in clear weather is 13.33 mph then speed in thunderstorm would be negative, which is not possible since speed can't be negative.

Hence, the speed in clear weather would be 50 mph, and in thunderstorm would be 20 mph less, i.e. 30 mph.

7 0
2 years ago
n 2018, homes in East Baton Rouge (EBR) Parish sold for an average of $239,000. You take a random sample of homes in Ascension p
Olenka [21]

Answer:

Conclusion

   There is no sufficient evidence to conclude that the mean of the home prices from Ascension parish is higher than the EBR mean

Step-by-step explanation:

From the question we are told that

   The population mean for EBR is  \mu_ 1  = \$239,000

    The sample mean for Ascension parish  is \= x_2  = \$246,000

   The  p-value  is  p-value  =  0.045

     The level of significance is  \alpha = 0.01

The null hypothesis is  H_o : \mu_2  = \mu_1

The  alternative hypothesis is  H_a  :  \mu_2 > \mu_1

Here \mu_2 is the population mean for Ascension parish

   From the data given values we see that  

          p-value  >  \alpha

So we fail to reject the null hypothesis

So we conclude that there is no sufficient evidence to conclude that the mean of the home prices from Ascension parish is higher than the EBR mean

3 0
1 year ago
At the beginning of the business day, a bank's vault held $575,900. By the end of the day, $(3.5 103) had been added to the vaul
Likurg_2 [28]

3.5*10^3=3,500

3,500+ 575,900=579,400

5 0
2 years ago
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