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Sati [7]
3 years ago
12

What is the value of y in the solution to this system of equations? 5x – 7y = 7 y = -5x + 3

Mathematics
1 answer:
zysi [14]3 years ago
7 0

Answer:

y = -0.5

Step-by-step explanation:

given

5x – 7y = 7    ------- eq 1

y = -5x + 3  (we rearrange this so that the terms are in the same order as eq 1)

-5x – y = -3   ----- eq 2

by elimination, eq 1 + eq 2

(5x – 7y) + (-5x – y) = 7 + (-3)

5x - 7y -5x - y = 7-3

-8y = 4

y = 4/(-8)

y = -0.5

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A sample of 26 offshore oil workers took part in a simulated escape exercise, resulting in the accompanying data on time (sec) t
solniwko [45]

Answer:

The upper confidence bound for population mean escape time is: 379.27

The upper prediction bound for the escape time of a single additional worker  is 413.64

Step-by-step explanation:

Given that :

sample size n = 26

sample mean \bar x =  371.08

standard deviation \sigma = 24.45

The objective is to calculate an upper confidence bound for population mean escape time using a confidence level of 95%

We need to determine the standard error of these given data first;

So,

Standard Error S.E = \dfrac{\sigma }{\sqrt{n}}

Standard Error S.E = \dfrac{24.45 }{\sqrt{26}}

Standard Error S.E = \dfrac{24.45 }{4.898979486}

Standard Error S.E = 4.7950

However;

Degree of freedom df= n - 1

Degree of freedom df= 26 - 1

Degree of freedom df= 25

At confidence level of 95% and Degree of freedom df of  25 ;

t-value = 1.7080

Similarly;

The Margin of error = t-value × S.E

The Margin of error = 1.7080 × 4.7950

The Margin of error = 8.18986

The upper confidence bound for population mean escape time is = Sample Mean + Margin   of  Error

The upper confidence bound for population mean escape time is =  371.08 +  8.18986

The upper confidence bound for population mean escape time is = 379.26986  \approx 379.27

The upper confidence bound for population mean escape time is: 379.27

b.  Calculate an upper prediction bound for the escape time of a single additional worker using a prediction level of 95%.

The standard error of the mean = \sigma \times \sqrt{1+ \dfrac{1}{n}}

The standard error of the mean = 24.45 \times \sqrt{1+ \dfrac{1}{26}}

The standard error of the mean = 24.45 \times \sqrt{1+0.03846153846}

The standard error of the mean = 24.45 \times \sqrt{1.03846153846}

The standard error of the mean = 24.45 \times 1.019049331

The standard error of the mean = 24.91575614

Recall that : At confidence level of 95% and Degree of freedom df of  25 ;

t-value = 1.7080

∴

The Margin of error = t-value × S.E

The Margin of error = 1.7080 × 24.91575614

The Margin of error = 42.55611149

The upper prediction bound for the escape time of a single additional worker  is calculate by the addition of

Sample Mean + Margin of Error

= 371.08 + 42.55611149

= 413.6361115

\approx 413.64

The upper prediction bound for the escape time of a single additional worker  is 413.64

8 0
4 years ago
Carmen mixes iced tea with 6 1/2 cups of lemonade. The entire mixture is 10 3/4 cups of liquid. What equation can you solve to f
masha68 [24]
10 3/4 - 6 1/2 the difference between these two will be your answer
7 0
3 years ago
Is (1, 9) a solution to this system of equations?<br> y = x + 8<br> y = 5x + 4
valentinak56 [21]

Answer:

yes

Step-by-step explanation:

To determine if (1, 9) is a solution, substitute x = 1 into the right side of the equations and if the result is y = 9 then it is a solution

y = 1 + 8 = 9 ← True

y = 5(1) + 4 = 5 + 4 = 9 ← True

Thus (1, 9) is a solution to the system of equations.

5 0
3 years ago
Read 2 more answers
Simply the expresstion: 5+8 (3 + x )
DIA [1.3K]
The answer is going to be 8x+29
7 0
2 years ago
Read 2 more answers
In the function y = -5x2 + 5 , the graph will open down, be shifted up 5 units, and it will be wider than the parent function y
masya89 [10]
We are considering the function y=f(x)=-5 x^{2} +5

the graph of this function is the graph of the parent function y=g(x)= x^{2} after applying the following steps.

1. multiply by -1:

-x^{2} is x^{2} reflected with respect to the x-axis.


2. multiply by 5:

-5x^{2} is -x^{2} shrinked towards the y axis. 

for example, consider x=1/2

 -5x^{2}=-5( \frac{1}{2} )^{2}=-5* \frac{1}{4}= \frac{-5}{4}=-1.25

 -x^{2}=- ( \frac{1}{2} )^{2}=- \frac{1}{4}=-0.25

now this means that -5x^{2} is "lower" than -x^{2}, which means there is a shrinking of the graph.

3. add 5:

-5 x^{2} +5 is -5 x^{2} shifted 5 units up.


4.

so the graph of the function a) opens down, b) is shifted 5 units up, c) is not wider than the parent function



Answer: False
6 0
4 years ago
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