a+a+1+a+2+a+3+a+4+a+5=159
6a=159-15
6a=144
a=24
a)x={1,2,3,4,5,6,7,8,9}
z={0,1,2,3,4,5,6,7,8,9}
y=0,5
aplicand principiu produsului, rezulta 9*10*2=180 de numere
b)z=x+1
y=x+2
xx(x+2)x(x+1)=60
faci calculele si afli pe x (asta daca ex. e corect scris si nu cumva are bara deaspra nr=60)