Wicked Inclinations

Dear Sensei:

Hello! I was wondering if you could tell me how I can tell if a slope is positive (+) or negative (-). I can't stand it when I get the numbers on the slope correct, but I get the answer wrong because it was negative! Help me!

Your friend, 

George Glass

George, I wish I could have saved you from this mathematical head-scratcher earlier. But the good news is that once you learn, you will hopefully never forget.

When you are reading a sentence, you read it from left to right (assuming you're reading in English or other European languages, that is).

It's the same thing when you are looking at a slope. You need to begin on the left, and move to the right in order to tell if it's positive or negative.

If the line goes uphill, it's positive! You're going uphill.

If the line goes down, it's negative. You're going downhill, so it's going in a negative direction.

So if you look at the lines above, the one on the left could be 2/3, but the one on the right would be -2/3. 

I hope this helps, and that you have a positive week, and stay tuned for more mathematical know-how here at Mr. Carter's Dojo.