Simon measures the depth of water in centimeters in his fish tank at the end of each day his measurements are shown.

which equation shows the water depth y, in the fish tank after x days.

D

Step-by-step explanation:

y = -1/2x + 18.5

check it by inserting the day number and comparing with the chart

y = -1/2(2) + 18.5

y = -2/2 + 18.5

y = -1 + 18.5

y = 17.5

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:

44

step-by-step explanation: