Question

(а+а2+…+а2007)/(а-1+а-2+…+а-2007)=

Answer 1

Ответ:

(a+a2+...+a2007)/(a-1+a-2+...+a-2007)=a(1+2+3...+2007)/a(-1-2-3...-2007)=1+2+3...+2007/1-2-3-4...-2007= -1