探索题:(x-1)((x+1)=x2-1,
(x-1)(x2+x+1)=x3-1,
(x-1)(x3+x2+x+1)=x4-1,
(x-1)(x4+x3+x2+x+1)=x5-1.
(1)观察以上各式并猜想:
①(x-1)(x6+x5+x4+x3+x2+x+1)=________________________;
②(x-1)(xn+xn-1+xn-2+…+x3+x2+x+1)= ________________________;
(2)请利用上面的结论计算:
①(-2)50+(-2)49+(-2)48+…+(-2)+1
②若x1007+x1006+…+x3+x2+x+1=0,求x2016的值.