Question 403125
y=2x-6
x=0, y=-6 (0,-6)
y=0,x=3(3,0)

y=-6 is a line parallel to the x axis
plot the points
The system ahs one solution (0,-6) as can be seen from the graph

{{{drawing(300,300,-5,5,-10,5,grid(1),graph(300,300,-5,5,-10,5,y=-6,y=2x-6))}}}