Ta có:
\(A=x^8-2017x^7+2017x^6-2017x^5+...+2017x^2-2017x+25\)
\(=\left(x^8-2016x^7\right)+\left(-x^7+2016x^6\right)+...+\left(x^2-2016x\right)-x+25\)
\(=\left(x-2016\right)\left(x^7-x^6+...+x\right)-x+25\)
Thế x = 2016 vào A ta được
\(=\left(2016-2016\right)\left(2016^7-2016^6+...+2016\right)-2016+25=-2016+25=-1991\)
Ko biet lam quen cach lam rui hihihi ^,^
A=x^8-(x+1)x^7+(x+1)x^6-(x+1)x^5+...+(x+1)x+25
A=x^8-x^8-x^7+x^7+x^6-x^6-x^5+...+x^2+x+25
A=2016+25=2041
t nhầm chút A=x^8-x^8-x^7+x^7+...-x^2-x+25
A=-2016+25=-1991
vi X=2016 nen X+1=2016+1=2017 thay x-1=2017va bieu thuc A ta co tu lam nhe
