Answer:
A line that rises from left to right has positive slope.
Step-by-step explanation:
A horizontal line just goes from left to right but not up or down so y does not change at all. Change in y/change in x makes slope. Since y does not change, it has 0 slope which isn’t no slope.
A vertical line moves up and down but not left to right so there is no change in x. You cannot divide by 0 if you follow the equation y/0. So slope is undefined.
A line that rises from left to right goes in a diagonal direction is like a 2d hill. It is positive because change in y would be positive and change in x would be also positive. Positive/positive is positive making the slope positive.
A line that falls from right to left literally gives the same line so that means it is also positive slope, not negative.