Răspuns :
Salut,
a) 399 – (b : 4) = 390 <=>
b : 4 = 399 – 390 <=>
b : 4 = 9 <=>
b = 9·4 <=>
b = 36 <=>
S = {36}
b) 36 : (555 – e) = 4 <=>
555 – e = 36 : 4 <=>
555 – e = 9 <=>
e = 555 – 9 <=>
e = 546 <=>
S = {546}
...........................................................
a) 399 – (b : 4) = 390 <=>
b : 4 = 399 – 390 <=>
b : 4 = 9 <=>
b = 9·4 <=>
b = 36 <=>
S = {36}
b) 36 : (555 – e) = 4 <=>
555 – e = 36 : 4 <=>
555 – e = 9 <=>
e = 555 – 9 <=>
e = 546 <=>
S = {546}
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