Answer:
Associative Property of Addition.
Step-by-step explanation:
It states that no matter how the numbers are ordered, the result will be the same. Feel free to look it up on google for more information :)
Time=distance/speed
621÷51.75
=12
So it takes 12 hours
ANSWER

EXPLANATION
The given equation is

Take antilogarithm of both sides to base e.

This will simplify to

Group like terms to obtain,


Take square root of both sides to get,
r/3 + t = w to get r by itself (Which I think is your question)
r/3 + t = w subtract t from both sides
r/3 = w - t and times by 3 on both sides
r = 3(w-t)
Answer:
░░█░░░░░░▄██▀▄▄░░░░░▄▄▄░░░█
░▀▒▄▄▄▒░█▀▀▀▀▄▄█░░░██▄▄█░░░█
█▒█▒▄░▀▄▄▄▀░░░░░░░░█░░░▒▒▒▒▒█
█▒█░█▀▄▄░░░░░█▀░░░░▀▄░░▄▀▀▀▄▒█
░█▀▄░█▄░█▀▄▄░▀░▀▀░▄▄▀░░░░█░░█
░░█░░▀▄▀█▄▄░█▀▀▀▄▄▄▄▀▀█▀██░█
░░░█░░██░░▀█▄▄▄█▄▄█▄████░█
░░░░█░░░▀▀▄░█░░░█░███████░█
░░░░░▀▄░░░▀▀▄▄▄█▄█▄█▄█▄▀░░█
░░░░░░░▀▄▄░▒▒▒▒░░░░░░░░░░█
░░░░░░░░░░▀▀▄▄░▒▒▒▒▒▒▒▒▒▒░
░░░░░░░░░░░░░░▀▄▄▄▄▄░░░░░█
Step-by-step explanation: