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Graphically subtracting vectors

Watch Sal determine which diagram represents vector subtraction graphically. Created by Sal Khan.
Video transcript
These are vectors A and B all right.That's Vector A.That's vector B Which of the following describes the valid way of obtaining vectorA-vector B So lets look at our choices right over here So,here they just depicted vectorA just like its depicted It may be shifted over a little bit and then here they depicted vector A-The negative of vector A Looks like you are taking the negative of vector A and to that you are adding vector B and then they are claiming that this magenta vector is A-B But this one right over if we know what they wrote over here What they done is that they added a negative A to a B So this is the negative of vector A + vector B or we can think of it as vector B-vector A so this one right over here is not right. If we swap the sign this was a negative A + B.Then we will say "O.K this is accurate" but they want us to figure out about ways of obtaining A-B and this isn't that.this B-A So we take the other choice So you have vector A. You start with the tail of vector A to the head of vector A and then over here at the tale of the negative of vector B So they essentially flipped it over when you take the negative of it. And so adding negative B to A and then so, if you take the tail of where we started to the tail of where we ended Yes.This would be vector A+negative vector B which is the same thing as vector A-vector B. So that one is right. That's a valid way of obtaining vector A-vector B.