Răspunsuri

2014-10-09T10:13:28+03:00
7a+9b+9c+7d=7(a+d)+9(b+c)=7x10+9x20=70+180=250
a+b+c+d=30,(a+d)+(b+c)=30,10+(b+c)=30,b+c=30-10=20
asociativitatea
Marcheaza-l daca e cel mai bun raspuns.Multumesc!