Răspunsuri

2014-05-29T11:18:27+03:00
A+a+1+a+2+a+3+a+4+a+5+a+6+a+7+a+8+a+9+...a+18=27

18a+ (1+18)*18/2 =27

18a+19*9=27

18a+171=27

18a=27-171

18a= -144

a= -8

a+1=-8+1=-7

a+2=-8+2=-6

a+3=-8+3=-5
.................
a+18=-8+18=10

a*(a+1)*(a+2)...+(a+18)=  -7* (-6)...*0..*10=0
orice nr inmultit cu 0 da 0