Me, i only get 2 chances to answer, and this is my last change, and i need with math so bad

G(x)=x2-16xb=-16, so =16 = 649(x) = (x2 - 16x + 64) - 649(x) = (x - 1)2-

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?

What is the value of x when x + 7 = 21?