Which of the following sets of values is a solution to the following system of linear equations?

4x + y = 24

x - y = -4

a.) x = 4,y =8

b.) x = 2,y = 6

c.) x = 1,y = 1

d.) x = 5,y = 4

also explain why.

A. find the power of the test, when the null hypothesis assumes a population mean of mu = 450, with a population standard deviation of 156, the sample size is 5 and the true mean is 638.47 with confidence intervals of 95 b. find the power of the test, when the null hypothesis assumes a population mean of mu = 644, with a population standard deviation of 174, the sample size is 3 and the true mean is 744.04 with confidence intervals of 95% c. find the power of the test, when the null hypothesis assumes a population mean of mu = 510, with a population standard deviation of 126, the sample size is 10 and the true mean is 529.44 with confidence intervals of 95