The original price of a fitness tracker is $85. It is on sale for 10% off. What is the sale price of the fitness tracker?

76.50

Basically move decimal point from 85.00 one place to the left which would become 8.50

You then subtract 85.00 by 8.50 and you'll get 76.50

hope that helps! have a good day

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: