find p(z ≤ -2.16)

Answer 1

From standard normal probability table: 0.0154.

Answer 2

Z is a standard normal random variable. To find probabilities of the standard normal random variable you must use the Standard Normal Distribution Table:

https://cnx.org/contents/SCdvoXS4@2/Using-the-Normal-Distribution

Be sure to look up the value -2.1 on the left margin to find the row and 0.06 on the top margin to find the column. The number where the row and column intersect is the probability you're looking for.