Răspunsuri

2014-09-28T18:37:29+03:00
2014-09-28T18:43:05+03:00
A+2b+c=51 adunam cu 2a+b+2c=42 ne da 3a+3b+3c=93 3(a+b+c)=93impartim la 3 a+b+c=31