(1)∵(x2-1)÷(x-1)=x+1,(x3-1)÷(x-1)=x2+x+1,(x4-1)÷(x-1)=x3+x2+x+1,(x5-1)÷(x-1)=x4+x3+x2+x+1,∴(xn-1)÷(x-1)=xn-1+xn-2+…+1,∴(x6-1)÷(x-1)=x5+x4+x3+x2+x+1;(2)∵(x6-1)÷(x-1)=x5+x4+x3+x2+x+1,∴x6-1=(x-1)(x5+x4+x3+x2+x+1).