this is valid?

[Semidevil]

prove that -(-a) = a.

my proof is that

-(-a) = -1*(-a) = -(-1*a) = -(-(1*a)) = a.

this is assuming we are using a bunch of already proved properties, i.e, they commute, and there exists a 1 identity..etc etc...

if this is wrong, any tips?

 

[Pepsi90919]

you have too much time on your hands

 

[Cobalt]

Negative multiplied by a negative equals a positive. I don't see what the problem is.

 

[Semidevil]

this is homework guys...not too much time.

anyways, yea, we all know that negative * negative is positive, and I just want to make sure when I write down this proof, because I want to be as precise as possible......not leave any details out.

 

[Cristatus]

welll.....since a = 1a, and -a = -1a, --a = a, and --1a = a, which is the same thing, yes 😀 but it's just pointless to do that unless you are a 6th/7th grade textbook

edit: speeling mistakes

 

[Cobalt]

Originally posted by: logic1485
welll.....since a = 1a, and -a = -1a, --a = a, and --1a = a, which is the same thing, yes 😀 but it's just pointless to do that unless you are a 6th/7th grade textbook

edit: speeling mistakes

Edit didn't work so well now did it? 😱