My sister is 14 years old. my brother says that his age minus 12 is equal to my sister's age. how old is my brother?

What’s the domain of this function? fastttt

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?

Tell whether the two rates form a proportion