Question

How do you find the slope of any line parallel to the line through points (19, 1) and (10, 2)?

Answer 1

All lines parallel to a line through the points `(19,1)` and `(10,2)` will have a slope of `(-1/9)`

Explanation:

All parallel lines have the same slope.

Given two points `(x_1,y_1)` and `(x_2,y_2)` the slope of the line through those points is (by definition)
`m = (Delta y)/(Delta x) = (y_2-y_1)/(x_2-x_1)`

For the given data points this becomes:
`m = (2-1)/(1-19) = -1/9`