Question

What is the solution to the system of equations represented by these two lines?

Answer 1

The solution of two equations/lines is their intersect point.
Therefore, there can only be one intersection point/solution, because these lines are neither parallel or identical.
In the graph you can see that they intersect at (x,y)=(2,3) which is your solution and option b or d as one of them seems to be mistyped :)

@question2
y=kx+b

both your equations share the same k=-2:
y=-2x+3
y=-2x-1

therefore these lines are parallel and don't have any intersection as they are always at different y values (the b)