The value of k is
<h3>How to solve the simultaneous equation?</h3>
Given:
x-y=k.............(eq i)
2x²+y²-15..............(eq ii)
We would make y the subject formula in eq ii
2x²+y²-15= 0
2x² + y²= 15
y²= 15-2x²
y=  ...........(eq iii)
...........(eq iii)
Substitute the value of y into eq i
x-( = k
= k
x- ( = k
= k
k= 
Read more about simultaneous equations here:
brainly.com/question/16863577
#SPJ1
 
        
             
        
        
        
Check the picture below.
![~\hfill \stackrel{\textit{\large distance between 2 points}}{d = \sqrt{( x_2- x_1)^2 + ( y_2- y_1)^2}}~\hfill~ \\\\[-0.35em] ~\dotfill\\\\ A(\stackrel{x_1}{1}~,~\stackrel{y_1}{-9})\qquad B(\stackrel{x_2}{8}~,~\stackrel{y_2}{0}) ~\hfill AB=\sqrt{[ 8- 1]^2 + [ 0- (-9)]^2} \\\\\\ AB=\sqrt{7^2+(0+9)^2}\implies AB=\sqrt{7^2+9^2}\implies \boxed{AB=\sqrt{130}} \\\\[-0.35em] ~\dotfill](https://tex.z-dn.net/?f=~%5Chfill%20%5Cstackrel%7B%5Ctextit%7B%5Clarge%20distance%20between%202%20points%7D%7D%7Bd%20%3D%20%5Csqrt%7B%28%20x_2-%20x_1%29%5E2%20%2B%20%28%20y_2-%20y_1%29%5E2%7D%7D~%5Chfill~%20%5C%5C%5C%5C%5B-0.35em%5D%20~%5Cdotfill%5C%5C%5C%5C%20A%28%5Cstackrel%7Bx_1%7D%7B1%7D~%2C~%5Cstackrel%7By_1%7D%7B-9%7D%29%5Cqquad%20B%28%5Cstackrel%7Bx_2%7D%7B8%7D~%2C~%5Cstackrel%7By_2%7D%7B0%7D%29%20~%5Chfill%20AB%3D%5Csqrt%7B%5B%208-%201%5D%5E2%20%2B%20%5B%200-%20%28-9%29%5D%5E2%7D%20%5C%5C%5C%5C%5C%5C%20AB%3D%5Csqrt%7B7%5E2%2B%280%2B9%29%5E2%7D%5Cimplies%20AB%3D%5Csqrt%7B7%5E2%2B9%5E2%7D%5Cimplies%20%5Cboxed%7BAB%3D%5Csqrt%7B130%7D%7D%20%5C%5C%5C%5C%5B-0.35em%5D%20~%5Cdotfill)
![B(\stackrel{x_1}{8}~,~\stackrel{y_1}{0})\qquad C(\stackrel{x_2}{9}~,~\stackrel{y_2}{-8}) ~\hfill BC=\sqrt{[ 9- 8]^2 + [ -8- 0]^2} \\\\\\ BC=\sqrt{1^2+(-8)^2}\implies \boxed{BC=\sqrt{65}}](https://tex.z-dn.net/?f=B%28%5Cstackrel%7Bx_1%7D%7B8%7D~%2C~%5Cstackrel%7By_1%7D%7B0%7D%29%5Cqquad%20C%28%5Cstackrel%7Bx_2%7D%7B9%7D~%2C~%5Cstackrel%7By_2%7D%7B-8%7D%29%20~%5Chfill%20BC%3D%5Csqrt%7B%5B%209-%208%5D%5E2%20%2B%20%5B%20-8-%200%5D%5E2%7D%20%5C%5C%5C%5C%5C%5C%20BC%3D%5Csqrt%7B1%5E2%2B%28-8%29%5E2%7D%5Cimplies%20%5Cboxed%7BBC%3D%5Csqrt%7B65%7D%7D)
now, we could check for the CA distance, however, we already know that AB ≠ BC, so there's no need.
 
        
             
        
        
        
 Answer:


And we can find the limits in order to consider values as significantly low and high like this:


Step-by-step explanation:
Previous concepts
A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".
The margin of error is the range of values below and above the sample statistic in a confidence interval.
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
Solution to the problem
For this case we can consider a value to be significantly low if we have that the z  score is lower or equal to - 2 and we can consider a value to be significantly high if its z score is  higher tor equal to 2.
For this case we have the mean and the deviation given:


And we can find the limits in order to consider values as significantly low and high like this:


 
        
             
        
        
        
Answer:
Check the explanation
Step-by-step explanation:
Y = 11.5 + 4.5*X1 -2.5*X2 +0.7*X3+1.6*X4 -2.4*X5 -2.8*X6
FOR JANE
X1 =1 , X2 =1 , X3 =5 , X4 =0 ,X5=0, X6=1
SO,
Y =11.5+(4.5*1)-(2.5*1)+(0.7*5)+0+0-(2.8*1)
= 14.2
..........................
FOR Sophie
X1 =1 , X2 =1 , X3 =10 , X4 =1 ,X5=0, X6=0
so,
Y =11.5+(4.5*1)-(2.5*1)+(0.7*10)+ (1.6*1)+0+0
= 22.1
 
        
             
        
        
        
8 for 6 is the answer I think