Reasons why minus times minus equals to plus

Reasons why minus times minus equals to plus

Have you ever wonder why we accept, in mathematics, that negative of negative gives positive sign(that is, negative times negative equals to positive)? I guessed you might have asked yourself this interesting question. Here are some reasons why we accept negative of negative to  be positive:

1. FROM THE LOGIC PERSPECTIVE: taking a statement for an example; I like that girl. "I like that girl" being a positive statement can be made negative by saying the opposite; I don't like that girl. We can as well make the latter statement positive, negative of the statement, by saying "I don't not like that girl" which simply means "I like that girl". When you say the opposite(negative) of a negative thing, then you are saying the positive.

2 FROM THE EQUATION PERSPECTIVE: consider these equations for example;
a.
0 = 0 x -1
0 = -1 + 1 x -1
0 = (-1 x -1) + (1 x -1)
0= (-1 x -1) - 1

If you have followed these equations carefully, you'll see that for the last equation to be correct, the answer to the right hand expression has to be zero. -1 x -1 has two results that can be suspected of, either -1 or +1 but in this case if -1 is chosen, the answer which is -2 does not equal zero, and therefore isn't the correct result of -1 x -1. Let's try and fix -1 x -1 as +1 and see if it does make the expression equals zero. "+1 - 1 = 0". Yes! and that proofs -1 x -1 = +1, minus times minus equals plus.

 b. FROM UNDERSTANDING OF DIVIDING ANYTHING BY ITSELF GIVES ONE: consider the following equations;

-2 x -2 = -2 x -2
-2 x -2 = (-1 x -1) x 2 x 2
-2 x -2 = -1/-1 x 2 x 2 (note that multiplication is the same as dividing by the reciprocal and the reciprocal of -1 is -1)
By intuitive reasoning, we know that anything divided by itself gives us one with only zero being an exception.
Therefore,
-2 x -2 = 1 x 2 x 2 = 4.