afla nr necunoscut 1128-b+54=813

Răspuns :

1 128 - b + 54 = 813

1 128 - b = 813 - 54

1 128 - b = 759

b = 1 128 - 759

b = 369
1128-b+54=813
1128-b=813-54
1128-b=759
b=1128-759
b=369

Verificare:1128-369+54=813