Look at these adjectives:
Tom est beau, mais Henri et Bob sont très beaux.
Tom is handsome, but Henri and Bob are very handsome.
Yvette est belle, mais Leila et Belinda sont très belles.
Yvette is beautiful, but Leila and Belinda are very beautiful.
C'est un bel animal parmi de beaux animaux.
It's a beautiful animal among beautiful animals.
Note that to form the masculine plural, adjectives ending in -eau add -x, and vieux doesn't change.
As for the feminine plural, it is regular and simply takes an -s.
BUT
The masculine forms bel, nouvel and vieil (when in front of a vowel) become the regular masculine plural beaux, nouveaux and vieux.
Examples and resources
J'ai acheté de nouveaux bols et de nouvelles assiettes.
I bought some new bowls and some new plates.
"Plurals in French" by www.frenchspanishonline.com
C'est un bel animal parmi de beaux animaux.
It's a beautiful animal among beautiful animals.
Regarde ces vieux hommes et ces vieilles femmes.
Look at these old men and these old women.
Yvette est belle, mais Leila et Belinda sont très belles.
Yvette is beautiful, but Leila and Belinda are very beautiful.
Ce vieil arbre est à côté de ces vieux arbres.
This old tree is next to these old trees.
Tom est beau, mais Henri et Bob sont très beaux.
Tom is handsome, but Henri and Bob are very handsome.
Mon nouvel ami s'entend bien avec mes nouveaux amis.
My new friend gets along with my new friends.
Q&A
Chris
Kwiziq community member
15/10/18
Anne
Kwiziq community member
7/03/17
Sar
Kwiziq community member
8/03/17
Aurélie
Kwiziq language super star
10/03/17
Laura
Kwiziq language super star
4/08/16
Janet
Kwiziq community member
15 October 2018
2 replies
from before
Is this right
Les nouveaux voisins sont arrives.
Les nouvelles voisines sont arrives.
Sorry I can't work the accent for arrives.
Chris
Kwiziq community member
15 October 2018
15/10/18
You need to accord the participle to the subject:
Les nouveaux voisins sont arrivés.
Les nouvelles voisines sont arrivées.
Janet
Kwiziq community member
15 October 2018
15/10/18