Why did he divide (x^10-1) and (x^2-1) by (x-1)? Can someone kindly explain that to me, please? I would really appreciate it. Thanks! :D <3####[['NULL', 'Instructor', 'NEU'], ['(x^10-1)', 'Mathematical_Related_Concept', 'NEU'], ['(x^2-1)', 'Mathematical_Related_Concept', 'NEU'], ['(x-1)', 'Mathematical_Related_Concept', 'NEU']]