afla necunoscuta
(55*7842+680)*0+550=a
(b-800):50+900=1000


Răspuns :

(55*7842+680)*0+550=a
0+550=a
a=550

(b-800):50+900=1000
(b-800):50=1000-900
(b-800):50=100
b-800=100x50
b-800=5000
b=5000+800
b=5800