Need on this! it is angles. what is the value of x and the measure of angle b?

What is the simplified expression for 6(2(y+x))

For the following geometric sequence, find the recursive formula. {-80, 20, -5, } i need : ')

Arandom sample of n = 25 observations is taken from a n(µ, σ ) population. a 95% confidence interval for µ was calculated to be (42.16, 57.84). the researcher feels that this interval is too wide. you want to reduce the interval to a width at most 12 units. a) for a confidence level of 95%, calculate the smallest sample size needed. b) for a sample size fixed at n = 25, calculate the largest confidence level 100(1 − α)% needed.