How do you subtract fractions? i don't get it.

What is the vertex form of f(x) = x2 + 6x + 3

Find the area of the regular hexagon if a side is 20 cm.

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?