The rectangular shapes are ...
... the flags of Monaco, Indonesia and Poland.
Ligue 1 is the football (soccer) top flight of France, but it also comprises clubs from Monaco, notably AS Monaco. Liga 1 is the top division of several countries, among them Indonesia.
The flags of Monaco and Indonesia have a similar design of two horizontal stripes, red (A) on top and white (B) at the bottom, so the last flag must be the flag of Poland, which has white on top and red at the bottom.
The flags have different proportions: Monaco's flag has 4:5; Indonesia's flag has 2:3 and Poland's flag has 5:8. That makes the width of Indonesia's flag 15 units.
The top football division of Poland is the Ekstraklasa.
The equations refer to ...
... bands. Pink Floyd was founded in 1965. Pink is a mexture of red (A) and white (B). White Zombie was founded in 1985. Finally, the Red Hot Chili Peppers were founded in 1983.
To wrap up, the symbols are:
X = 15
Y = Ekstraklasa
Z = Hot Chili Peppers
A = red
B = white