There is one solution for x and one solution for y. The solution is: x = -1 ; y = 2
many solutions
zero solutions. If you plot these two lines, you will see that they are parallel and do not intersect.
None because the discriminant is less than zero
2x - y = 8 x + y = 1 These are your two equations. They will have two solutions since you have two variables. The solutions are x=3 and y=-2
Only one: (3,-2)