I ONLY HAVE 20 MINUTES LEFT Functions f(x) and g(x) are composed to form h(x) = square root of x^3-2. If f(x) = square root of x+2 and g(x) = x^3+a, what is the value of a?

I think it’s D but I need an explanation why!!!

Arandom sample of 45 observations results in a sample mean of 68. the population standard deviation is known to be 23 a. compute the margin of error at a 959% confidence interval. b. compute the 95% confidence interval for the population mean c. compute the 90% confidence interval for the population mean. d. compute the 75% confidence interval for the population mean