Đề sai nha bn!!!
\(x^8-2005x^7+2005x^6-2005x^5+...-2005x+2005\)
Vì x = 2004 => x + 1 = 2005
\(\Rightarrow x^8-\left(x+1\right)x^7+\left(x+1\right)x^6-\left(x+1\right)x^5+...-\left(x+1\right)x+\left(x+1\right)\)
\(=x^8-x^8-x^7+x^7+x^6-x^6-x^5+...-x^2-x+x+1\)
\(=1\)
=.= hok tốt!!
Đề thiếu nha bạn, chỉnh chút: \(x^8-2005x^7+2005x^6-2005x^5+....-2005x+2005\)
\(x=2004\Rightarrow x+1=2004+1=2005\)
Thay vào biểu thức ta có:
\(x^8-2005x^7+2005x^6-2005x^5+....-2005x+2005\)
\(=x^8-\left(x+1\right)x^7+\left(x+1\right)x^6-\left(x+1\right)x^5+...-\left(x+1\right)x+\left(x+1\right)\)
\(=x^8-x^8-x^7+x^7+x^6-x^6-x^5+....-x^2-x+x+1\)
\(=1\)
P/s: sai sót xin bỏ qua
