PLEASE HELP. I need an answer by Nov 5 Fill in the missing reasons for the following two-column proof for the following information. Given: M is the midpoint of CD; CM = 3x – 10; MD = 6x – 22 Prove: x = 4

M is the midpoint of CD; CM = 3x – 10 ; MD = 6x - 22 1.?
CM=MD 2.?
3x – 10 = 6x – 22 3. substitution
-3x – 10 = -22 4. Subtraction Property of Equality
-3x = -12 5. ?
x=4 6. Division Property of Equality

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