\(\left(1-x\right)\left(x^{31}+x^{30}+...+x+1\right)=\left(1-x\right)\left(1+x\right)\left(1+x^2\right).....\left(1+x^{16}\right)\)
VP = 1 - x32
Đặt \(A=x^{31}+x^{30}+..+x+1\Leftrightarrow xA=x^{32}+x^{31}+.......+x^2+x\)
VT = \(A-xA=\left(1-x\right)A=1-x^{32}\)= VP (dpcm)