When we solve for y, we want to isolate y by itself. To do so in this equation, we can divide both sides of the equation by 62...
y = 434/62 = 7
Answer: option C is the correct answer
Step-by-step explanation:
The system of linear equations is
10x + 7y = 12 - - - - - - - 1
8x + 7y = 18 - - - - - - - 2
Since the coefficient of y is the same in equation 1 and equation 2, we will eliminate y by subtracting equation 2 from equation 1, it becomes
10x - 8x + 7y - 7y = 12 - 18
2x = -6
x = - 6/2 = - 3
Substituting x = - 3 into equation 1, it becomes
10×-3 + 7y = 12
-30 + 7y = 12
Let the constants be on the right hand side and the term containing y be on the left hand side. It becomes
7y = 12 + 30
7y = 42
y = 42/7
y = 6
C) (−3, 6)
Answer:
C.I. = (2.297, 11.703)
Step-by-step explanation:
The t-statistic for difference of mean is given by,
Here, 
= 84
= 7
s₁ = 4
n₁ = 12
s₂ = 6
n₂ = 18
Substituting all value in formula,
We get, t = -3.541 at 28 degree of freedom.
Using this formula, we get, t = 1.5342
Therefore, based on the data provided, the 99% confidence interval for the difference between the population means 
is: 2.297 < < 11.703
which indicates that we are 99% confident that the true difference between population means is contained by the interval (2.297, 11.703)
