Answer:
Let the cost of the video game be x
- Carter sold 9 of his video games online
He got $9x for selling 9 video games
- The next day, he sold 27 video games
He got $27x for selling 27 video games
- He collected a total of $900
According to the above problem, the equation we get is
![9x + 27x = 900 \\ 36x = 900 \\x=(900)/(36)\\ \boxed{ x = 25}](https://img.qammunity.org/2022/formulas/social-studies/high-school/fcv7i84ywnu78loovo8y50rrzi5sylnp7r.png)
Therefore, the cost of each video game is $25.