Answer:
Lower limit = 1007.95 cm/s
Upper limit = 1142.05 cm/s
Step-by-step explanation:
We have to calculate a 95% CI with population's standard deviation known.
The sample is size n=60, with mean M=1075.
The confidence interval can be expressed as:
For a 95% CI, the value of z=1.96.
(x, y) = (7, -5)
<h3>Step-by-step explanation:</h3>It generally works well to follow directions.
The matrix of coefficients is ...
Its inverse is the transpose of the cofactor matrix, divided by the determinant. That is ...
So the solution is the product of this and the vector of constants [-6, -50]. That product is ...
... x = (3·(-6) +(-4)(-50))/26 = 7
... y = (5·(-6) +2·(-50))/26 = -5
The solution using inverse matrices is ...
... (x, y) = (7, -5)