Mình không chép đề nhé, tại đề viết hơi cực
Ta có: $2013=2014-1=x-1$ thay vào $B$ ta có:
$B=x^{14}-(x-1).x^{13}-(x-1).x^{12}-(x-1).x^{11}-....-(x-1).x-(x-1)$
$=x^{14}-x^{14}+x^{13}-x^{13}+x^{12}-x^{12}+x^{11}-...-x^2+x-x+1$
$=1$
Ta có: $9=8+1=x+1$ thay vào $C$ ta có:
$C=x^{13}-(x+1)x^{12}+(x+1).x^{11}-(x+1).x^{10}+...-(x+1)x^2+(x+1).x-2$
$=x^{13}-x^{13}-x^{12}+x^{12}+x^{11}-x^{11}-x^{10}+...-x^3-x^2+x^2+x-2$
$=x-2$
$=8-2=6$
Ta có: $2013=2014-1=x-1;2015=2014+1=x+1$
Thay vào $D$ ta có:
$D=(x-1).x-(x+1).x^2+x^3$
$=x^2-x-x^3-x^2+x^3$
$=-x=-2014$
$F=x^5-(14+1)x^4+(14+2)x^3-(14+14+1).x^2+(14-1).x$
$=x^5-(x+1).x^4+(x+2).x^3-(2x+1).x^2+(x-1).x$
$=x^5-x^5-x^4+x^4+2x^3-2x^3-x^2+x^2-x$
$=-x=-14$
