What’s the answer? Help me !

Asimple random sample of size nequals14 is drawn from a population that is normally distributed. the sample mean is found to be x overbar equals 70 and the sample standard deviation is found to be sequals13. construct a 90% confidence interval about the population mean

Solve for n? [tex]z = \frac{3}{4} mn[/tex]

Find the roots of the polynomial function f(x) = x^3 + 2x^2 + x