I found the answer on multiple sites but can somebody please help me with the explanation as I did not find that anywhere.

Find the greatest common factor of the followig monomials 21u^5v,3u^4v^6, and 3u^2v^5

Runner ran 1 4/5 miles on monday and 6 3/10 on tuesday. how many times her monday’s distance was her tuesdays distance

Aladder that is 20ft long is leaning against the side of a building. if the angle formed between the ladder and the ground is 75 degrees how far is the bottom of the from the base of the building?