5x + y = 15
y = -5x + 15
Substituting y= -5x+15 from first equation into second equation:
3x + 2y = 16
3x + 2·(-5x + 15) = 16
3x - 10x + 30 = 16
-7x + 30 = 16
7x = 30 - 16 = 14
x = 2
Substituting x=2 into the first equation:
5x + y = 15
5(2) + y = 15
10 + y = 15
y = 15 - 10
y = 5
So your final answers are x=2 and y=5.
Answer: 
Step-by-step explanation:
Given : Sample size : n= 9
Degree of freedom = df =n-1 =8
Sample mean : 
sample standard deviation : 
Significance level ; 
Since population standard deviation is not given , so we use t- test.
Using t-distribution table , we have
Critical value = 
Confidence interval for the population mean :

90% confidence interval for the mean value will be :






Hence, the 90% confidence interval for the mean value= 
Answer:
I think it's D sorry if I get it wrong
Step-by-step explanation:
The answer to the problem is 12-6x
B=7
3(b-4)+5b=44
3b-12+5b=44
8b=44+12
8b=56
b=7