Răspunsuri

2014-10-02T17:50:23+03:00
7a+9b+9c+7d,stiind ca a+b+c+d=30 si a+d=10 => b+c=20
7a+7d+9b+9c=
7(a+d)+9(b+c)=
7*10+9*20 = 
70+180=250
4 5 4
Cel mai inteligent răspuns!
2014-10-02T18:00:07+03:00
7a+9b+9c+7d=7(a+d)+9(b+c)=7x10+9(b+c)=70+9(30-a-d)=70+270-
-(a+d)=340-10=330
marcheaza-l daca e cel mai bun raspuns.multumesc!