The heights of all the newborns in a certain country are normally distributed, with a mean of 20 inches and a standard
deviation of 2 inches. A mother just delivered a baby that is 21
inches long. Which of the following represents the a score of
the baby's height? (Round your answer to two decimal
places.)
A. 0.50
B.-0.50
C.-1.50
D.1.50

The answer is c

Step-by-step explanation:

since your problem is x^4 = 81, what you have to undeo is the "to the fourth power" part.

the inverse (opposite operation) of "to the fourth power" is "to the fourth root".

  (x^4) ^ ¼   = 81 ^ ¼  

  81 = 3^4     so (3 ^ 4) ^ ¼   =   3 ^ 1   = 3

by hand: (3 ^ 4) ^ ¼   =   3 ^ (4 x ¼) = 3 ^ 1   = 3   (when you take a power to a power, multiply the exponents.)

or, do it by calculator. one way of finding the fourth root is to use ^ (1/4)

step-by-step explanation:

126 maybe. sorry