观察下列各式: (x-1)(x+1)=x2-1;
(x-1)(x2+x+1)=x3-1;
(x-1)(x3+x2+x+1)=x4-1;
… … …
(1)根据规律填空 (x-1)(xn+xn-1+…+x+1)=__ __________.
(2)根据规律计算 2100+299+298+297+…+22+2 +1= .
(1) xn+1-1 (2) 2101-1
观察下列各式: (x-1)(x+1)=x2-1;
(x-1)(x2+x+1)=x3-1;
(x-1)(x3+x2+x+1)=x4-1;
… … …
(1)根据规律填空 (x-1)(xn+xn-1+…+x+1)=__ __________.
(2)根据规律计算 2100+299+298+297+…+22+2 +1= .
(1) xn+1-1 (2) 2101-1