Factor completely. 25a^4-10a^2z^2-8z^4 really need . i have been struggling with this for 20 min.

The parabola y = x² - 4 opens: a.) up b.) down c.) right d.) left

At a cost of 200, your club bought 175 frisbees to sell at the pep rally. you plan on selling them for $5 each. what is the domain of the function?

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.