What does the y-intercept represent in this situation

These question are hard can you me with answers

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?

Cos^2x+cos^2(120°+x)+cos^2(120°-x)i need this asap. pls me