What do the mathematical expressions in the image represent?

Analysis:

The image displays two mathematical equations presented vertically, aligned with a curly brace connecting them, indicating they form a system of equations.

The first equation is y + 0.5x = 3.

The second equation is y + 0.5x = -3.

The curly brace signifies that these two equations are to be considered together as a system.

The number 1. is also visible in the top right corner, suggesting this might be the first problem in a set.