Please help , will mark

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

Hector and alex traded video games. alex gave hector one fourth of his video games in exchange for 6 video games. then he sold 3 video games and gave 2 video games to his brother. alex ended up with 16 video games. how many video games did alex have when he started?

How many terms does the polynomial x^2 y^2 have