|a - b| = |b - a|

Susan123456 · **Posted:** Sun, 13 Sep 2009 21:30:22 UTC

Hello,

I need to prove |a - b| = |b - a|. What I got so far is ||a| + |-b||. I need to have some more steps before proving the consequent is equal to the antecedent but I don't know how to do the intermediate steps. Could someone give me a hint or two?

Thank you,

Matt · **Joined:** Wed, 1 Oct 2003 04:45:43 UTC **Posts:** 9632

Susan123456 wrote:

I need to prove |a - b| = |b - a|

There are three cases:

(1) a = b, in which case a - b = b - a = 0.

(2) a < b, in which case a - b < 0 and b - a > 0.

(3) a > b, in which case a - b > 0 and b - a < 0.

Susan123456 · **Posted:** Mon, 14 Sep 2009 02:49:27 UTC

thank you very much

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|a - b| = |b - a|

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