Predict the result
Find the slope through the labeled points negative five comma one and negative one comma zero.

Set up the model
Slope is vertical change divided by horizontal change.
Subtract both coordinates in the same point order.

Work the example
The vertical change is negative one and the horizontal change is positive four.
The slope is negative one fourth.

Check the result
Find the slope through negative three comma negative four and five comma two.
Take eight seconds to think before the answer appears.
[Eight-second silent pause to work; the answer remains hidden.]
The rise is six and the run is eight, giving slope three fourths.

Interpret the result
A vertical line has undefined slope; a horizontal line has zero slope.