Problem 244
What happens to the value obtained for the slope if the coordinates of the two ordered pairs aren’t subtracted in the same order? Give an example as part of your explanation.
Solution
If we do not subtract them in same order we will get an opposite sign slope, which is wrong.
Example: two points are (1, 2) and (3,4)
slope=
\frac{2}{-2}
\frac{4-2}{3-1} = 
=1
Now we can see the first slope is opposite to the correct slope.