The solution the graph is given as (2, -3). Note that this is the point on the graph where the graph of both functions intersect.
Imagine you have two friends, and each of them gives you clues about where they are in a city. The first friend says they are 6 blocks away in one direction and 1 block in another.
You can represent this as 6x + y = 9, with x and y being how far they moved in each direction. The second friend says they are 4 blocks in one direction but 1 block in the opposite.
This is 4x - y = 11. The point where both friends meet is the solution, and you find it by graphing these lines, seeing where they intersect.