Sam and Chris went to “Lots O Fun” to play laser tag and video games for Chris’s birthday. Sam played 3 games of laser tag, 5 video games, and spent $17 total. Chris played 4 games of laser tag, 7 video games, and spent $23 total. How much does one video game cost to play?

L=laser tag, V=video games

3L+5V=17 (1)
4L+7V=23 (2)
Since the question asks only about the video games, we want to eliminate the L's. We can do this by multiplying the first equation by 4 and the second equation by -3.
12L+20V=68 (3)
-12L-21V=-69 (4)
Add 3 and 4 together.
-V=-1
V=1
Video games are $1 each. If you had to solve for laser tag, you would the substitute v=1 into equation 1 or 2.