Đường tròn (c) đi qua điểm m(2;1) và tiếp xúc với hai trục toạ độ Ox Oy có phương trình là

Can any one me with the answers to these questions asap?

This is so hard and it’s for a test

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?