Nouns ending in x show possession by adding an apostrophe -s ('s) to the end of the word. Examples:
The fox's tail was matted and muddy.
We met Max's mother at the meeting.
The possessive form of the name Alex is Alex's.Examples: Alex's bicycle is black. Max's bicycle is blue. Felix's bicycle is red.
Apostrophes are never used to form the plural of any proper noun. The Herberts will attend. not: The Herbert's will attend. Add -s to make most last names plural. Add -es to those that have endings with sounds such as ch (as in Hatch, but not as in Bach), s, sh, x, and z. Example: The Joneses will tour Hong Kong. Like most plural nouns, plural proper nouns have a single apostrophe after the plural ending to indicate possession. Example: The reception will be at the Herberts' home, Bryan House.
It would entirely depend on the specific word's origin. And the vast majority of the nouns ending in u, end in a diphthong (two or more vowels), and the most correct answer in that case would be "add s".
As with names ending in S, Z, CH, and SH, the plural adds an ES. E.g. the Fox family are the Foxes.
A name for a person who has a LEAN head lool x x x
Phoenix
Ibex
Pheonix
ApteryxOryxArchaeopteryx (extinct)FoxOxIbex
It ends with the "x". For example: Fox, Alex, Lex, Marx, Rex.
mouse
Destination X: Hawaii and Destination X: California
math. when you need to show what X is and the name of a function
Any number with an ending digit of 0, 2, 4, 6 or 8 is divisible by 2.
The TV show Samurai X is the story of a Japanese warrior. His name is Kenshin and he helps people who need protecting, as he is a former assassin. There is an official Samurai X Youtube channel.
The possessive form of the name Alex is Alex's.Examples: Alex's bicycle is black. Max's bicycle is blue. Felix's bicycle is red.
Possibly Criminal Minds or X-Files