2006-09-21 13:37:56 · 6 answers · asked by David S 1 in Education & Reference ➔ Homework Help
Each number has an "additive inverse" associated to it (a sort of "opposite" number), which when added to the original number gives zero. This is in fact the reason why the negative numbers were introduced: so that each positive number would have an additive inverse.
For example, the inverse of 3 is -3, and the inverse of -3 is 3.
Note that when you take the inverse of an inverse you get the same number back again: "-(-3)" means "the inverse of -3", which is 3 (because 3 is the number which, when added to -3, gives zero). To put it another way, if you change sign twice, you get back to the original sign.
Now, any time you change the sign of one of the factors in a product, you change the sign of the product:
(-something) × (something else) is the inverse of (something) × (something else), because when you add them (and use the fact that multiplication needs to distribute over addition), you get zero.
For example, is the inverse of , because when you add them and use the distributive law, you get .
So is the inverse of , which is itself (by similar reasoning) the inverse of .
Therefore, is the inverse of the inverse of 12; in other words, the inverse of ; in other words, 12.
The fact that the product of two negatives is a positive is therefore related to the fact that the inverse of the inverse of a positive number is that positive number back again.
2006-09-21 13:40:51 · answer #1 · answered by Anonymous · 0⤊ 0⤋
You have a negetive (opposite of positive) number of something which you multiply negatively (this time means opposite of negative) which makes a positive number of that object.
2006-09-21 13:42:10 · answer #2 · answered by tim_bit_ca 1 · 0⤊ 0⤋
It follows from the distributive sources and the definition of a unfavourable selection. enable x be some beneficial selection. Then, by definition, the selection -x is the unique selection which would be further to x to furnish a sum of 0. it is, x + (-x) = 0. enable y be yet another beneficial selection. Then -y is unfavourable, and x + (-x) = 0 -y(x + (-x)) = y(0) (-y)x + (-y)(-x) = 0 -(yx) + (-y)(-x) = 0 (this follows from the incontrovertible fact that (-y)x = (-1y)x = -a million(yx) = -(yx)) including yx to the two factors supplies (-y)(-x) = yx considering x and y have been arbitrary beneficial numbers, this proves that the made of any 2 negatives is inevitably beneficial.
2016-10-17 10:16:06 · answer #3 · answered by Anonymous · 0⤊ 0⤋
think of it as a grammatical statement for example
2x-2=-4
just like if you siad i am not going to clean my room ( one negative word which is not ) this obviously means what it sayd however if the problem is -2x-2=+4 then it is like saying i am not going to not clean my room ( if you are not going to not do something then that means you ARE going to do that particular thing) is that easier to understand
2006-09-21 13:57:01 · answer #4 · answered by dothechacha 2 · 0⤊ 0⤋
Because two wrongs make a right.
Nah, i agree with the other guys, but they got in before i could finish writing mine.................
2006-09-21 13:44:31 · answer #5 · answered by Game Theorist 2 · 0⤊ 0⤋
SORRY. NOT YOUR MOM BUT A MOM.....DO YOUR OWN HOME WORK....................
2006-09-21 13:49:30 · answer #6 · answered by BLOODHOUND 6 · 0⤊ 0⤋