HELP ASAP pls!just say wether there positive or negative

Answer:
Line 1 = Negative
Line 2 = Zero
Line 3 = Positive
Line 4 = Undefined
Step-by-step explanation:
Line 1's gradient is negative since it's sloping down.
Line 2's gradient stays at 0 since it does not go upwards or downwards.
Line 3's gradient is positive since it's tilting upwards.
Line 4's gradient is undefined since the line shoots up on the same point on the x-axis so the gradient cannot be determined by a single rational number.