The graph shows the two lines corresponding to the equations:

1. $x - y = 3$ (in blue)
2. $7x - y = -3$ (in green)

The red point $(-1, -4)$ marks the solution where the two lines intersect. This is the solution to the system of equations.

Do you have any questions, or would you like more details on any part of this process?

Here are 5 related questions to consider:

1. What are some other methods to solve systems of equations besides substitution?
2. How would the graph look if the system had no solution (parallel lines)?
3. What happens if the system has infinitely many solutions?
4. How can you use matrix methods to solve a system of equations?
5. What is the geometric interpretation of solving systems of equations?

Tip: To solve a system of equations efficiently, always check if substitution, elimination, or graphical methods might be faster depending on the form of the equations.