Answer:
Line 1: zero
Line 2: negative
Line 3: undefined
Line 4: positive
Explanation:
Line 1 => slope is horizontal. The slope of horizontal lines are always equal to 0. Therefore, the slope of line 1 is zero.
Line 2 => the line slants downwards form our left to the right, this implies there is a decline or increase. Thus, the slope would be negative.
Line 3 => the line of a vertical line is always undefined. Line 3 slope is therefore undefined.
Line 4 => the slope slants upwards from our left to the right. This indicates a rising slope or an increase. Therefore, the slope of line 4 is positive.