[Math] Slope of a line

[t1497f35]

Hi,
please see screenshot.
The author of the book says that the travel from (4,-1) to (-3,9) is -10/7, shouldn't it be 10/-7 instead since traveling from (4,-1) to (-3,9) you actually go up left (and not down right)?

Same type of mistake he's apparently made in the last paragraph.

Or am I mistaken?

[Vaphell]

lines have no direction so it doesn't matter.
(-10)/(7) = (10)/(-7) = -(10/7) it's the same thing, but yes, he should have his examples switch places.

[t1497f35]

...but yes, he should have his examples switch places.
Thanks, that's what I've been wondering.

[Bachstelze]

In general (i.e. unless stated otherwise), positive distances are when you are traveling to the right, regardless of whether it is up or down.

[ofnuts]

lines have no direction so it doesn't matter.
(-10)/(7) = (10)/(-7) = -(10/7) it's the same thing, but yes, he should have his examples switch places.Jumped the gun.Forget it...

[StephenF]

Either way -10/7 is the simplified form.