Answer:
see explanation
Step-by-step explanation:
A line sloping upwards from left to right has a positive slope.
A line sloping downwards from left to right has a negative slope.
A horizontal line parallel to the x- axis has a slope of zero
A vertical line parallel to the y- axis has an undefined slope
Hence
Graph 1 has a positive slope
Graph 2 has a negative slope
Graph 3 has a slope of zero
