Which system of equations has exactly one solution? 2 x minus 4 y = 8. x + y = 7.
3 x + y = negative 1. 6 x + 2 y = negative 2.
3 x + 3 y = 3. Negative 6 x minus 6 y = 3.
3 x minus 2 y = 4. Negative 3 x + 2 y = 4.

Use the given degree of confidence and sample data to construct a confidence interval for the population mean mu . assume that the population has a normal distribution. a laboratory tested twelve chicken eggs and found that the mean amount of cholesterol was 185 milligrams with sequals 17.6 milligrams. a confidence interval of 173.8 mgless than muless than 196.2 mg is constructed for the true mean cholesterol content of all such eggs. it was assumed that the population has a normal distribution. what confidence level does this interval represent?