a=g mancate de 1 canar
b=g mancate de 1 papagal
5a+4b=880 b=(880-5a)/4
2a+3b=520
2a+3(880-5a)/4=520
8a+2640-15a=2080
7a=560
a=80 g mananca un canar
b=(880-5×80)/4=(880-400)/4=480/4=120 g mananca 1 papagal
3×80+5×120=240+600=840 g mananca 3 canari si 5 papagali