(1) (x^n - 1)÷(x-1)=x^(n-1)+x^(n-2)+x^(n-3)+······+x³+x²+x
(2)1+2+2²+……+2⁶² + 2⁶³
=(1-2)(1+2+2²+……+2⁶² + 2⁶³)/(1-2)
=(1-2⁶⁴)/(-1)
=2⁶⁴-1
(1) (x^n - 1)÷(x-1)=x^(n-1)+x^(n-2)+x^(n-3)+······+x³+x²+x
(2)1+2+2²+……+2⁶² + 2⁶³
=(1-2)(1+2+2²+……+2⁶² + 2⁶³)/(1-2)
=(1-2⁶⁴)/(-1)
=2⁶⁴-1