Answer:
14) 
15) 
16) 
Step-by-step explanation:
In order to calculate the slope of a line, we can use this formula:

The procedure is:
- Choose two points on line.
- Substitute the coordinates into the formula and evaluate.
Then:
14) Point (0,0) and Point (1,2):
Slope: 
15) Point (0,0) and Point (-2,2):
Slope: 
16) Since it is an horizontal line, the slope is zero:
