To determine which line the point lies on, you can just plug in one of the numbers into the equations to see if it equals out.
(2, -1) I will use the 2 and plug it in for x in the equation.
y = 2x + 1
y = 2(2) + 1
y = 5 The point does not lie on this line because when x = 2, y = 5 (2, 5)
y = x + 5
y = 2 + 5
y = 7 The point does not lie on this line because when x = 2, y = 7 (2, 7)
y = 2x - 5
y = 2(2) - 5
y = 4 - 5
y = -1 The point does lie on this line because when x = 2, y = -1 (2, -1)
y = x - 2
y = 2 - 2
y = 0 The point does not lie on this line because when x = 2, y = 0 (2, 0)
