Răspuns :
a+b=252;
a=b+42 --> b+42+b=252 (se inlocuieste in prima) --> 2b=252-42--> 2b=210 --> b=210/2 --> b=105;
--> a= 105+42=147;
a=b+42 --> b+42+b=252 (se inlocuieste in prima) --> 2b=252-42--> 2b=210 --> b=210/2 --> b=105;
--> a= 105+42=147;