Răspuns :
(a+105)*3+20=356
(a+105)*3=356-20
(a+105)*3=336
a+105=336:3
a+105=112
a=112-105
a=7
Baftă!....
(A+105)•3+20=356
(A+105)•3=356-20
(A+105)•3=336
A+105=336:3
A+105=112
A=112-105
A=7
(A+105)•3=356-20
(A+105)•3=336
A+105=336:3
A+105=112
A=112-105
A=7